A quick troubleshooting question for you all. Hopefully quick.
A short while ago it came to my attention the AC Condensor fan (or Radiator Blower Motor, for the Advance Auto guys out there) had seized. This fan is always supposed to be free moving.
So, I replaced the fan. New fan is free moving but still doesn't spin when the AC is turned on. I did some trouble shooting via the FSM.
There are two connectors going to the motor. A Brown/White wire line connector and a non descript complete black one. With the AC on, the Brown/White one gives me 12 volts. However, I get nothing on the other connector. If I understand this right, the Brown/White line runs to the AC Relay (Brown capped in the relay box beneath the clean air intake) and, I'm guessing, the other line runs to the Thermoswitch. When I short the non descript black line connector on the fan, with the AC on (hence, completing a circuit), it spins wonderfully.
So, the question becomes, is it the thermoswitch that's bad or is it the wiring line to the thermoswitch between the AC Relay and the switch? I'm inclined to say it's the thermoswitch, as the condensor fan doesn't even turn on after prolonged engine running (say, 3 hours of driving). What's a quick test to check this without having to remove the fan shroud and taking it off the lower radiator hose?
Can anyone give me a rough estimate on the cost of said thermoswitch (as the Advance Autos, NAPAs, etc of this area don't have it in their inventory)?
Any insights would be greatly appreciated.
Danke!
-kirk
1990 240sx, Condensor fan not spinning. Thermoswitch or wiring harness?
Re: 1990 240sx, Condensor fan not spinning. Thermoswitch ... (RamonetB)
Okay, I'll amend that. They DO have it in their catalog as a Radiator Fan Switch. Well, that makes sense.
You learn something everday.
-kirk
You learn something everday.
-kirk
Re: (NISTECH)
Not yet,
As near as I can figure it, it's either the thermoswitch or the fuseable link. I haven't gotten to testing either yet. I'm assuming I'm on the right track since no one has said other wise.
I'll post back with my results. I try to post the solutions I come across, as I'm always frustrated when doing a search the post simply ends leaving one wonder what the conclusion was.
-kirk
As near as I can figure it, it's either the thermoswitch or the fuseable link. I haven't gotten to testing either yet. I'm assuming I'm on the right track since no one has said other wise.
I'll post back with my results. I try to post the solutions I come across, as I'm always frustrated when doing a search the post simply ends leaving one wonder what the conclusion was.
-kirk
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benemorius
- Posts: 1937
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- Car: s13, s13, eg, e36
Re: (RamonetB)
If the fan kicks on when you short the wires running to the thermo switch, then there can't be a problem with a fuse or the wiring to the relay. Either the wiring to the thermo switch is bad (doubt it), the thermo switch is bad (possible), or the coolant temp isn't getting high enough to trigger the thermo switch (how hot is the weather where you are?)
Re: (benemorius)
It's been in the 80's the past week, Benemorius.
But isn't the condensor fan supposed to spin up as soon as the AC is turned on, temperature aside?
-kirk
But isn't the condensor fan supposed to spin up as soon as the AC is turned on, temperature aside?
-kirk
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benemorius
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- Car: s13, s13, eg, e36
Re: (RamonetB)
No. The whole purpose of that connector going to the temp switch in the lower coolant hose is to only engage the fan when the coolant temp goes over a predetermined temperature. Unfortunately I can't tell you what that temperature is.
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benemorius
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Re: (NISTECH)
Ok, I'm looking at the service manual right now and it does suggest that the fan should be off unless the temp sensor in the lower radiator hose is sensing greater than 198-208*F. Given that most Nissan cars are fwd, I presume that the 240 may be different because it's rwd configuration places the radiator and condensor together as bascially one unit collectively cooled by the belt-driven radiator fan.
Re: (benemorius)
That would seem to make sense. I got the same impression. However, most mechanics I talk to insist it should come on as soon as the AC is turned on.
I don't suppose anyone here in the forums has an 89 or 90 (and I imagine the 91-94s are the same) 240sx that they could just quickly check to see if the fan spins when the AC comes on?
I still suspect the Thermoswitch to be bad, as the fan has NEVER come on, even when driving for several hours in 80 degree weather. I just need to get off my lazy butt and jack the car up and get at it.
Either way, it'd be nice to know exactly how this is supposed to work. My AC is STILL intermittent, and I know it's NOT the relays or the environmental controls. However, the AC light on the controls still fluctuates. This has to be something in the wiring in the car or something else I'm missing. Again, the lights on the AC fluctuates, sometimes going on and sometimes not, but it's never indicative of whether the AC is actually on. And on really hot days the AC will run longer before the car just starts cycling or before kicking it off completely -- that's if it starts at all. On hot days it tends to have more trouble starting than others.
Slowly tracking it down.
I don't suppose anyone here in the forums has an 89 or 90 (and I imagine the 91-94s are the same) 240sx that they could just quickly check to see if the fan spins when the AC comes on?
I still suspect the Thermoswitch to be bad, as the fan has NEVER come on, even when driving for several hours in 80 degree weather. I just need to get off my lazy butt and jack the car up and get at it.
Either way, it'd be nice to know exactly how this is supposed to work. My AC is STILL intermittent, and I know it's NOT the relays or the environmental controls. However, the AC light on the controls still fluctuates. This has to be something in the wiring in the car or something else I'm missing. Again, the lights on the AC fluctuates, sometimes going on and sometimes not, but it's never indicative of whether the AC is actually on. And on really hot days the AC will run longer before the car just starts cycling or before kicking it off completely -- that's if it starts at all. On hot days it tends to have more trouble starting than others.
Slowly tracking it down.
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benemorius
- Posts: 1937
- Joined: Tue Jun 08, 2004 5:39 pm
- Car: s13, s13, eg, e36
Re: (RamonetB)
Yes. I have two. The thing is - I've converted them both to 134a and rigged the fan to stay on constant to help make up for the decrease in refrigerant efficiency. I will say this - 198-208*F is at normal operating temperature, so by all rights the fan should come on so long as the engine is fully warmed up. And especially it should come on in hot weather.
You never mentioned you were actually having a/c trouble. Did you have another thread for that? Give some more details and we'll see about sorting that out, too. If you're saying that the green a/c light comes and goes, then it can either be electrical or refrigerant pressure related. If electrical, such a problem would have to lie between the controls and the ecu and the dual pressure switch - nowhere else. As far as pressure goes, you really ought to find someone qualified to monitor the pressures and see what's going on.
You never mentioned you were actually having a/c trouble. Did you have another thread for that? Give some more details and we'll see about sorting that out, too. If you're saying that the green a/c light comes and goes, then it can either be electrical or refrigerant pressure related. If electrical, such a problem would have to lie between the controls and the ecu and the dual pressure switch - nowhere else. As far as pressure goes, you really ought to find someone qualified to monitor the pressures and see what's going on.
Re: (benemorius)
Hrmm..
Yes, I did have a seperate thread for the AC issues. I'll have to dig it up. It kind of died, especialy once I realized the old condensor fan had seized. That kind of became a primary concern of mine.
Yes, I did have a seperate thread for the AC issues. I'll have to dig it up. It kind of died, especialy once I realized the old condensor fan had seized. That kind of became a primary concern of mine.
OLD AC thread.
Ah yes, here is the old thread:
zerothread?id=168795
Incidentally, the heat works now. Turns out a small bypass hose on the engine had a small leak in it that would vent coolant. But it was so small it only ever leaked a little on the engine and almost never enough to see any dripping. This was the cause of the loss of effective heating after awhile. I asked a mechanic to due a pressure test on the system and there it was, a very fine small thread of coolant!
An update on the "whining" of the compressor. It seems to have diminished greatly since I replaced the belts in the engine. Otherwise, things pretty much remain the same.
I haven't checked voltages yet on the compressor. But I have replaced or tested all the relays (including the Brown Cap condensor / AC compressor fan relay... that was a PAIN to find. BTW, this was the only relay that actually had some strange behaviour to it) in the AC system. So now they all check out fine. "New" Used Environmental controls put in (which I was told worked flawlessly in the old car, and since it performs identically to my "old" unit, which I've stripped down to the circuit board and tested the components, I assume both are in good condition).
You suggested possible wiring issues between the controls and the ECU and the pressure switch. I would like to add that whoever had the car before me put in an alarm system. Judging from the way it's wired up, they did it themselves as it is an ugly rats nest, spliced and capped, and no longer works. I plan on removing this junk.
But if this starts in on a new AC discussion, I'll start up a more adequate thread or revive the old one.
zerothread?id=168795
Incidentally, the heat works now. Turns out a small bypass hose on the engine had a small leak in it that would vent coolant. But it was so small it only ever leaked a little on the engine and almost never enough to see any dripping. This was the cause of the loss of effective heating after awhile. I asked a mechanic to due a pressure test on the system and there it was, a very fine small thread of coolant!
An update on the "whining" of the compressor. It seems to have diminished greatly since I replaced the belts in the engine. Otherwise, things pretty much remain the same.
I haven't checked voltages yet on the compressor. But I have replaced or tested all the relays (including the Brown Cap condensor / AC compressor fan relay... that was a PAIN to find. BTW, this was the only relay that actually had some strange behaviour to it) in the AC system. So now they all check out fine. "New" Used Environmental controls put in (which I was told worked flawlessly in the old car, and since it performs identically to my "old" unit, which I've stripped down to the circuit board and tested the components, I assume both are in good condition).
You suggested possible wiring issues between the controls and the ECU and the pressure switch. I would like to add that whoever had the car before me put in an alarm system. Judging from the way it's wired up, they did it themselves as it is an ugly rats nest, spliced and capped, and no longer works. I plan on removing this junk.
But if this starts in on a new AC discussion, I'll start up a more adequate thread or revive the old one.
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benemorius
- Posts: 1937
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- Car: s13, s13, eg, e36
Re: OLD AC thread. (RamonetB)
I'm going to go ahead and revive the old one.
Re: OLD AC thread. (benemorius)
No offense taken to the AC post.Well, I hope things have gone better since you post here.
I understand what you're saying about the oil levels and coolant. I'll have to make an attack plan on how to handle that.
BUT, I did figure out that this thermoswitch, or maybe a fusible link, certainly doesn't work. Nice long hot ride yesterday, temperatures in the 90's, and my engine temperature started to go up. Had to turn the heater on to keep the temp in a comfortable range.
During this time the condensor / radiator fan never came on. The fan itself works, as I've tested it. So, I'm feeling the switch. I'll post back more when I get it out of the car.
I understand what you're saying about the oil levels and coolant. I'll have to make an attack plan on how to handle that.
BUT, I did figure out that this thermoswitch, or maybe a fusible link, certainly doesn't work. Nice long hot ride yesterday, temperatures in the 90's, and my engine temperature started to go up. Had to turn the heater on to keep the temp in a comfortable range.
During this time the condensor / radiator fan never came on. The fan itself works, as I've tested it. So, I'm feeling the switch. I'll post back more when I get it out of the car.
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benemorius
- Posts: 1937
- Joined: Tue Jun 08, 2004 5:39 pm
- Car: s13, s13, eg, e36
Re: OLD AC thread. (RamonetB)
Sorry I never did remember to go back and finish that. Basically the bottom line is that you need to take it to someone qualified and have the whole system emptied and well flushed before starting over fresh with new refrigerant and oil and drier. Unfortunately ever since DIY a/c work became so popular, this has become all but necessary. You just never know who worked on it last and what they did.
Re: OLD AC thread. (benemorius)
yea my condensor fan doesnt come on either, and if i use the a/c, itll be ok for a few minutes then the engine temp will go up and up. i might just hot wire the damn thing and have it turn on with a switch or something. im here in florida and its hot as hell getting in the car after work. it sucks !
Re: OLD AC thread. (torque2go)
Well, I know my condensor fan works, as I can short the connection going to the thermal switch and it spins up fine.
So, my theory is this:There are two possible reasons why the condensor fan isn't working. 1) Something wrong with the thermal switch.2) Something wrong with the green fusable link that runs to the battery.
Since the fan spins, I assume the green fusable link is good. Else, I wouldn't get power. Thus, that leaves the thermal switch. Either it's coated in gunk or the switch is bad. Have to get in there to replace it and check it out.
Which I plan on doing this weekend as I help my brother disassemble the steering column on his DeLorean. I need to replace the thermostat in my 240 anyway. I did a while back thinking it would solve a leak. I replaced it with a cheapo part from Advance auto. Now I have over heating issues on top of no condensor fan!! Good thing I still have the old thermostat.
I'll let you know what I find.
So, my theory is this:There are two possible reasons why the condensor fan isn't working. 1) Something wrong with the thermal switch.2) Something wrong with the green fusable link that runs to the battery.
Since the fan spins, I assume the green fusable link is good. Else, I wouldn't get power. Thus, that leaves the thermal switch. Either it's coated in gunk or the switch is bad. Have to get in there to replace it and check it out.
Which I plan on doing this weekend as I help my brother disassemble the steering column on his DeLorean. I need to replace the thermostat in my 240 anyway. I did a while back thinking it would solve a leak. I replaced it with a cheapo part from Advance auto. Now I have over heating issues on top of no condensor fan!! Good thing I still have the old thermostat.
I'll let you know what I find.
Re: OLD AC thread. (RamonetB)
Hey, how did this all turn out? I'm having the same problem with my AC now. I'm in pretty much the same boat where when I short the fan it comes on just fine. My AC is working fine, as far as the light coming on and the clutch spinning. I am working on finding an R12 pressure gauge right now, and I think I have one.
If this was your thermal sensor that was at issue, how hard was it to replace? And how expensive did it get?
I've read this thread twice now and I feel a complete lack of fulfillment because I never know how this project turned out.
If this was your thermal sensor that was at issue, how hard was it to replace? And how expensive did it get?
I've read this thread twice now and I feel a complete lack of fulfillment because I never know how this project turned out.
Re: OLD AC thread. (inshje01)
My apologies on your discontentment, but it wasn't until this past weekend that the issue has finally been resolved.
First, the brief:The thermal switch that turns the condensor fan on is located in a metal connecting pipe (the switch itself screws in to this piece) which is fitted between your radiator and the radiator hose on the LOWER side, that is the lower radiator house, or the one towards the ground that leads to the thermostat.
Replacing it can be an easy or moderate task. You MIGHT be able to get to it from the passanger side front tire. It's right there, if you were to look at it. But if it's screwed in tightly, I don't think you'll get enough torque to get it out. Otherwise, the fan shroud has to come out and you can get to it from above. I had to remove the piece that it screws into to finally unscrew the switch, putting a rathcet through the pipe to offer enough leverage to the wrench working the switch.
BTW, best to drain your radiator fluid when doing this else it's going to gush out.
Some specifications:The thermoswitch is supposed to come on when it senses a temperature of roughly 204 degrees. Types vary widely in the sense that some turn on at 198 and others at 208. I removed mine and tested it using a digital meat thermometer (you know, the kind you stick in meat to see the internal temperature) a pot of hot water, and a multimeter. Set the multimeter for continuity and test the two prongs on the plug of the thermoswitch.
YOU SHOULD GET NOTHING. An open circuit, in other words. With the thermometer reading the temperature, bring it up to about 200 to 204 degrees. Hold the switch so that it rests IN the water (NOT on the bottom of the pan) for about 15 seconds to make sure it heats up. See if you have continuity now. If not, raise the temperature. If the switch fails to come on by 208 degrees, the switch is faulty and needs to be replaced. This part can be bought from Advance Auto for roughly $20.
As I said earlier, my switch WORKED. So I was still confused as to why my condensor fan wasn't turning on. that's when I had a stroke of luck.
The termperature here in PA soared to 95 degrees this past week. That's when I noticed my car overheated (after I put the OLD thermostat back in. I agree with others on this forum, don't skimp on the thermostat. Get a Nissan or Nismo part). It simply couldn't stay cool. Driving for 20 minutes and she'd start to get seriously hot. Forget the AC, it'd heat up even faster. With the heater on, I could control the heat of the car somewhat, but she was still running hot. Thus, I inspected the radiator hoses.
The top radiator hose was scorcing hot!! I couldn't touch it for more than a second or two. The bottom one though... I could touch that for more than 10 seconds before getting uncomfortable. Obviously, my condensor fan would NEVER come on if the temperature in the coolant of the lower radiator hose never got hot enough to turn it on!! Scorching top radiator hose, relatively cool lower hose? I had a perfect superior cooling radiator!!!
NOT. Obviously, with the car overheating, this meant my radiator was clogged. And sure enough, after turning the car off, there were areas of higher temperatures on the radiator when I touch it with my hand. That and the crap I keep seeing on my radiator cap.
A new radiator and new cap later, my car runs very cool and the AC works better than ever (although, still intermittent at times, but that's for another day) and my condensor fan run perfectly now!
As a side note, when I put my thermoswitch back in, I change it's orientation somewhat. Originally it was putting straight up. When I put it back together, it is now more at a 45 degree angle, towards its side. I did this on a whim in case I had some air in my system and it was getting stuck around the switch. I've properly bled the system now, so whether or not it helped, I don't know. But the car works so I'm happy.
I hope that helps you out!
As for my AC woes, I think I'm just going to take it to an AC specialist and have the system evacuated, tested, and recharged. I'm tired of banging my head on that one. Of course... it could still be the crappy wiring job the previous owner did with his alarm system... I still have to rip all that out.
Peace!
First, the brief:The thermal switch that turns the condensor fan on is located in a metal connecting pipe (the switch itself screws in to this piece) which is fitted between your radiator and the radiator hose on the LOWER side, that is the lower radiator house, or the one towards the ground that leads to the thermostat.
Replacing it can be an easy or moderate task. You MIGHT be able to get to it from the passanger side front tire. It's right there, if you were to look at it. But if it's screwed in tightly, I don't think you'll get enough torque to get it out. Otherwise, the fan shroud has to come out and you can get to it from above. I had to remove the piece that it screws into to finally unscrew the switch, putting a rathcet through the pipe to offer enough leverage to the wrench working the switch.
BTW, best to drain your radiator fluid when doing this else it's going to gush out.
Some specifications:The thermoswitch is supposed to come on when it senses a temperature of roughly 204 degrees. Types vary widely in the sense that some turn on at 198 and others at 208. I removed mine and tested it using a digital meat thermometer (you know, the kind you stick in meat to see the internal temperature) a pot of hot water, and a multimeter. Set the multimeter for continuity and test the two prongs on the plug of the thermoswitch.
YOU SHOULD GET NOTHING. An open circuit, in other words. With the thermometer reading the temperature, bring it up to about 200 to 204 degrees. Hold the switch so that it rests IN the water (NOT on the bottom of the pan) for about 15 seconds to make sure it heats up. See if you have continuity now. If not, raise the temperature. If the switch fails to come on by 208 degrees, the switch is faulty and needs to be replaced. This part can be bought from Advance Auto for roughly $20.
As I said earlier, my switch WORKED. So I was still confused as to why my condensor fan wasn't turning on. that's when I had a stroke of luck.
The termperature here in PA soared to 95 degrees this past week. That's when I noticed my car overheated (after I put the OLD thermostat back in. I agree with others on this forum, don't skimp on the thermostat. Get a Nissan or Nismo part). It simply couldn't stay cool. Driving for 20 minutes and she'd start to get seriously hot. Forget the AC, it'd heat up even faster. With the heater on, I could control the heat of the car somewhat, but she was still running hot. Thus, I inspected the radiator hoses.
The top radiator hose was scorcing hot!! I couldn't touch it for more than a second or two. The bottom one though... I could touch that for more than 10 seconds before getting uncomfortable. Obviously, my condensor fan would NEVER come on if the temperature in the coolant of the lower radiator hose never got hot enough to turn it on!! Scorching top radiator hose, relatively cool lower hose? I had a perfect superior cooling radiator!!!
NOT. Obviously, with the car overheating, this meant my radiator was clogged. And sure enough, after turning the car off, there were areas of higher temperatures on the radiator when I touch it with my hand. That and the crap I keep seeing on my radiator cap.
A new radiator and new cap later, my car runs very cool and the AC works better than ever (although, still intermittent at times, but that's for another day) and my condensor fan run perfectly now!
As a side note, when I put my thermoswitch back in, I change it's orientation somewhat. Originally it was putting straight up. When I put it back together, it is now more at a 45 degree angle, towards its side. I did this on a whim in case I had some air in my system and it was getting stuck around the switch. I've properly bled the system now, so whether or not it helped, I don't know. But the car works so I'm happy.
I hope that helps you out!
As for my AC woes, I think I'm just going to take it to an AC specialist and have the system evacuated, tested, and recharged. I'm tired of banging my head on that one. Of course... it could still be the crappy wiring job the previous owner did with his alarm system... I still have to rip all that out.
Peace!