89 240sx; Strange s13 Relay problem with AC and headlights...

[comablack783]

headlight problem - when i first got the car the headlights were working just fine for about the first 3 months or so, then they stopped going down. i discovered if i pushed the relay in the pic they would go down. if i push it alittle they go down a little, if i hold the relay down they go down all the way. ive tried playing with/jiggling the wires behind the relay and nothing, they only seem to go down when pressure is applied to the relay, also tried swapping the relay with a friends relay that i know works for sure, and nothing. any ideas?

AC problem - a while after i got the car i decided to get the AC fixed, the previous owner said it need freion(sp). i took it to a place and they filled it up, but it still wasnt blowing cold, after that the guy that did the work said it might be an electrical problem. he checked the fuses and the relays, then he took out a tester and pulled the AC relay out of the box and said that it might be a bad relay. after that he rigged a jumper and it worked, AC was cold. he told me to replace the relay ASAP. i went and pulled several relays from the junkyard (about 8) and none of em seem to work, the only way i can get the AC to work is with that jumper. i took it back to the guy and he was stumpped. I wouldnt mind leaving the jumper in but i have a feeling the AC is on 24/7 and it might be messing up the car, when im on the expressway and the AC buttons are off (depressed) i can feel cold air comming through the vents as if it were on (im in florida, no such thing as cold air, ITS ALWAYS HOT!). also the Idling on the car is off, its "supposed" to idle at around 750 rpms. my car sits at 900 and doesnt move even when the AC is on. when i use a relay it sits like a rock at 750 RPM, when i turn the AC on the RPMs move up to about a 1000 and then periodically come back down (which i belive is how its supposed to work) even though its not blowing cold air.

do you guys think chainging the harness would solve the problem? is there a way of changing it from the relay box back? like does it come in sections? the car is an 89 240sx. is there anyway of fixing it my self?

[NISTECH]

You have a connection issue with your HL relay. Likely a wire under it has a open circuit or is corroded in the terminal area. Your A/C sounds like a command issue. When the relay is installed and you push the a/c button does the condensor fan come on? Also does all the other controls for you climate control work properly, i.e. interior fan speeds,mode selector,temp adjuster?

[comablack783]

Ive played with the HL terminal before, like i poked and tugged around at the wires while the relay was connected to see if they would come down and nothing. should i try swaping that one relay terminal?

as far as I know when the relay is connected the condenser doesnt work thats what makes the AC cold right? everything else works except that the air comming through isnt cold. Ive been running this set up without a problem close to 8 months now (im a student, no money for an electrician). however last week the control box went dead, it kept blowing out the AC fuse. the minute the ignition was switched on the fuse would go. last saturday I swapped the control box and put another fuse, it worked until last night when it started taking fuses again.. its not just blowing them out, its obliterating the fuses, I believe its a nasty short. I didnt mention this before since i assumed that changing the control box had solved the problem .. doh..

heres a pic of what it did to a red(10), and a green (30 fuse). ohh btw before all this started happening it was using a 15 which is how i bought the car.

[NISTECH]

You have a nasty short in your harness somewhere. I dont know if I have diagrams of your circuit. I will have to look. I would be suspicious of the relay box though as both relays are in there and playing with the relay makes the circuit for the lights work.

[comablack783]

so do you think that changing out the harness including the relay box would likely solve the problem?

[NISTECH]

It may. The A/C issue could be in the other harness under the dash though. Its hard to say without probing cicuits for shorts. I dont have any manuals for pre 92 s-13's

[comablack783]

I dont know if you would be willing to Down Load one, but heres a link.

http://extranet.sessys.com:8800/media/90FSM.zip

it may not be an official FSM but thats pretty much all i can find online. i could never understand the wiring diagrams in these things, if you could tell me what to probe for that would be awesome.

[NISTECH]

I am DLong it I will review it and get back to you.

[comablack783]

cool man, thanks

[matt black]

i have the excect same problem with my ac ... it just happened when i swaped a ka24de into my 89 240sx..i am going to test some more wiring on the ac on monday.if i cant get it working, i plan to have it looked at on tuesday ..i will keep u updates on what i find.. i am in florida also and i have to have ac in this weather .. i am really thinking that is has something to do with the pressure sensor on the dryer ... the only ac stuff i change was the evap,condensor,compressor,and all the ac lines during the swap
Modified by matt black at 12:27 AM 9/5/2005

[NISTECH]

cool man, thanks

Are you familier with how to use a volt meter? I reviewed the diag. Your gonna have to do some pin checks. I dont mean a test light either.

[comablack783]

No i dont know how to use it, but I might no someone who does, what pin checks are you referring to and how do i check them with the volt meter?

[NISTECH]

ok With the key on car not running ,a/c switch not pushed. Check for 3 powers at the relay socket. You have to use a volt meter for electronic circuits. Make sure you have fresh fuses in there before you do this.

There are more steps but I am not going to over load you all at once since your a novice with electrical.

[comablack783]

ok kool, give me 2 or 3 days to hook up with my friend who has a volt meter, ill post as soon as i have the results.

[matt black]

ok With the key on car not running ,a/c switch not pushed. Check for 3 powers at the relay socket. You have to use a volt meter for electronic circuits. Make sure you have fresh fuses in there before you do this.

There are more steps but I am not going to over load you all at once since your a novice with electrical.

i checked the volts on mine and i got:#6 12.06v#3 12.11v#1 12.13v

i that correct?? i have the exact same problem as him with my ac..accept i am not blowing fuses.
Modified by matt black at 3:51 PM 9/8/2005

[NISTECH]

That is correct but your problem is something else.

[matt black]

Quote »AC problem - a while after i got the car i decided to get the AC fixed, the previous owner said it need freion(sp). i took it to a place and they filled it up, but it still wasnt blowing cold, after that the guy that did the work said it might be an electrical problem. he checked the fuses and the relays, then he took out a tester and pulled the AC relay out of the box and said that it might be a bad relay. after that he rigged a jumper and it worked, AC was cold. he told me to replace the relay ASAP. i went and pulled several relays from the junkyard (about 8) and none of em seem to work, the only way i can get the AC to work is with that jumper. i took it back to the guy and he was stumpped. I wouldnt mind leaving the jumper in but i have a feeling the AC is on 24/7 and it might be messing up the car, when im on the expressway and the AC buttons are off (depressed) i can feel cold air comming through the vents as if it were on (im in florida, no such thing as cold air, ITS ALWAYS HOT!). also the Idling on the car is off, its "supposed" to idle at around 750 rpms. my car sits at 900 and doesnt move even when the AC is on. when i use a relay it sits like a rock at 750 RPM, when i turn the AC on the RPMs move up to about a 1000 and then periodically come back down (which i belive is how its supposed to work) even though its not blowing cold air. [/quote]i have this exact same problem .. i took my 89 240sx to an a/c repair place and told them my problem ..they said they would look at it and let me know..i left the car there for 2 days ..when i went to pick it up they said "sorry we could not find the problem" ...they recommended taking it to the dealership..

[NISTECH]

The failure may act the same but you are missing the key failure which is the fuse blowing. Yours may not be working due to a bad thermo control or pressure switch problem.

[comablack783]

matt are you running a ghetto jumper to make your AC kick on too? that system worked for awhile before it died on me recently... i miss my cold ac . btw, i got a volt meter, but i cant make heads or tails out of it, im going to ask my dad how to use it possibly tommorow and ill post results asap.

[matt black]

iya i am using the same ghetto jumper.. my 240 looks just like the one in your sig...mine is the same color with gun metal wheels

[comablack783]

matt, thats pretty cool, do you have the lip too? is it a coupe?

ok so i finally figured out how to do the test, i plugged the negative from the volt meter into the negative from the batter terminal and probed the relay terminal as per the directions. I found the 3 powers,

dont have have a pic so bare with me here...______|[1] [2]||[3] [4]| -----------[5]| |[6]

readings where as follows.. 1 - 12.502 - 12.516 - 12.50

the rest were 0s. anything else i should be probing?

[matt black]

ya i have the lip too . but mine is a fastback

[NISTECH]

That means you have power available to all 3 circuits. I assume you have reinstalled the fuse at this point and it didnt blow? So it would be safe to assume your short is not between source and the relay. You now need to check the ground circuits on how you have them listed. Do nothing with terminal 2 that leads to the ECM and is not going to cause your fuse to blow. with the key on you are first going to check terminals 4 and 5 as you have them listed. You need to unplug the components on those lines. then check for continuity to ground there should be none. If there is, the one that had it is shorted somewhere between the relay box and the component to ground. The 2 components you will be unplugging is the ac compressor and the electric cooling fan.

[comablack783]

how do i unplug these items? for instance the compressor, should i go into the engine bay and look for a plug around the actual compressor and disconect it? also what electric fan are you talking about? the blower? thanks, sorry for the newbish questions.

[NISTECH]

There is a plug right on the compressor. The fan is loactaed against the radiator infront of your mechanical fan. follow its wire harness to its connector.

[comablack783]

Ok, first off I just wanna say, NISTECH, u are the man! Everything you’ve said so far has been right on the money... I found both plugs, the electric fan plug looked like it had been chewed by rats, wire was split and rubbing against the fan and the other wire was also split, I taped them up with electrical tape and plugged it back in. I've noticed that this fan does not turn on even after driving long distances, I also checked my brothers 240sx same year s13 and his doesn’t turn on either? I tried to check for continuity but I couldn’t figure out what you meant or where to set this thing to for continuity checking, I've included a pic of the volt meter, if you could explain it that would be great. After fixing the fan I changed the fuse and put the key and it took the fuse again. Do you think I should swap the fan out for a used one from the junkyard that might be in better shape?

[NISTECH]

Ok try this unplug you fan connector and retry the fuse thing. See if it pops it agian. with the fan unplugged when you turn the key on. If it doesnt get a new fan.

On the meter to do a basic continuity test or check resistance set your meter on the 200 ohms scale. To check for power and voltage drops use the 20volt scale.

[comablack783]

Ok, with a fresh fuse, volt meter set to 200 OHM, the negative from the volt meter in the negative terminal of the battery, the ac compressor and electric fan unplugged, and the key on, the readings I got where: ______|[1] [2]||[3] [4]|-----------[5]| |[6]

200 ohm scale : 3 – 26.04 – 15 – 1

on the 20k volt scale I got(I couldn’t find 20volt in the OHM scale so I figured you forgot the K)3 – 0.34 – 15 – 1

I tried probing the terminals from the top, the side, and even the bottom to make sure the positive was making contact and I getting a reading, that’s what I came up with each time. I tried to follow your instructions to the letter, but im sure I did it right since the volt meter reads 1 on the 200 ohm scale right off the bat even when its not plugged into anything, Let me know if there is something I missed and I’ll do it again.

[NISTECH]

Dude thats not 1 you have in your display. That means there is infinit resistance. In other words no continuity. The 20 volt scale I was talking about is under DC volts. along the same lines as what you doing. find the DC 20 volt scale. have your negetive on the battery and your red lead in the relay sockets. You need to find 3 12 volt [ or close to] readings. This would be with the key in the on position and nothing plugged in. Fuse in though. After you locate the 12 volt readings you need to do the 200 ohms reading on 2 of the other 3 terminals that dont have voltage. The 2 that are farther apart you do not want to ohm check the one that didnt have voltage. That goes to the ECM and it is not safe to ohm check control modules. The key to these tests is what you find on the 2 terminals that didnt have voltage on the first part of the check.

ON youtr meter your 20 volt setting is the middle one in Vdc .

[comablack783]

Ok, I finally got a chance to run the tests again, sorry for the delay, was busy with school. followed your directions to the letter. AC/electric fan unplugged, fresh fuse in, key on, negative in the negative, postive in the relay and the results where :

|[1] [2]||[3] [4]|-----------[5]| |[6]

- 20 VDC -1 = 12.302 = 12.316 = 12.29

- 200 OHM -3 = 02.54 = 1 (so im getting infinite resistance here?)5 = 1 (so im getting infinite resistance here?)

what does all that mean? also, just a note, when i ran the OHM tests on socket 3 of the relay for the first second it would read -1 then jump to 02.5. sockets 4, and 5 came up as 1's or as you said before, infinite resistance. what next?

edit-

you asked me to unplug the electric fan and try my jumper rig, I did, with the fan unpluged, fresh fuse in and jumper in it blows the fuse. with the relay in it doesnt blow the fuse but the compressor wont kick on, same thing happens with the electric fan plugged in. do you think I need a new fan?