94 Q45 HVAC ISSUES! HELP!

[bigrich3]

Was told it was blower motor, bought brand new blower motor, replaced it, still nothing! Tried 3 different resistors, still nothing. Put old blower motor & old resistor back on, and AC came on! Then it went off! Tested blower motor and resistor, they are both good. Every great once in a while, the AC/Heater will come on. For the most part, we just hear a couple of clicks and then nothing happens. What's going on and how do we fix it???

[Infinitiguy19]

Whats the problem exactly? Does the fan work only at high speed? Does the fan work at any other speed other than high?

Have you performed the diagnostic listed in the service manual?

[bigrich3]

We don't know what the problem is! If you're asking about the fan up by the radiator, it works fine. But, nothing will happen at all besides the clicking from the blower motor when we turn on the AC or heater. Sometimes, very rarely, when it wants to, the AC or heater WILL work...when it does come on, the AC is cold and the heater is hot....blower motor is good, resistor is good, and relay is good....we're thinking it might be a wiring problem, but haven't got a clue at where to start with the wiring. And we don't have a service manual. All we have is the owner's manual that came with the car and we've found nothing in there.

[goody90q45]

Here's the FSM for the 95Q. I posted it since it has an index and the 94 FSM doesn't. Both are the same.

http://www.nicoclub.com/FSM/Q45/1995_Q45/

Just to make sure...you're talking about the blower motor behind the glove box? And you've replaced the fan control amplifier with new or just the Darlington resistor which is a component of the amp? Did you clean all the caked-on dirt off the plastic blade assembly attached to the blower motor?

The amp and blower motor are usually the only two components of the cabin air system that fail. I've never heard of the relay going bad but it should have been a standardized relay that you can switch with one of the same color. Other than wiring the only other failure might be the controller itself but they're not a common failure item either. You could find one cheap on ebay or our parts forum and swap it in. Good luck.

[bigrich3]

Yes, the blower motor behind the glove box and the Darlington resistor. We have replaced both of those with brand new parts, still nothing. Put the old parts back on and that's when it all kicked in for a few minutes. When it does come on, it only stays on briefly. We are just completely baffled here! Can you explain a little more to me about the fan control amplifier? Maybe post a picture of what it looks like? And, thanks for the link for the service manual! We're definitely fixing to go through that thing too!

[Infinitiguy19]

Like I said perform the diagnostic which should take no longer than 5 minutes. Do it in direct sun light so the sun sensor code does not come up.

Or check to see that the blower motor connector is receiving the correct power as said in the service manual.

[goody90q45]

This is a fan control amplifier. The darlington resistor is a small component inside the amp that you need soldering skills to get to. The amp is mounted in the airbox behind the glovebox. Can't miss it.

[bigrich3]

Yeah, we replaced that whole thing with a brand new one...still got the same result, which was nothing! We don't have a diagnostic tool to use. Where can we get one? And thanks for your patience with me on this!

[Infinitiguy19]

Go to page HA-40 to run the Diagnostic through the HVAC display.