I see a lot of miss information here and unanswered threads. A lot of us who own 1985 and 1986 TPI cars have a Single Fan with No Switch. It seems there are a ton of old threads going back to circa 2006 or so where the Single Fan with No Switch fails and the owner can't figure out how to get it to work. Every response tells them to replace the switch even though there isn't one.

I can't believe in 20 years of this forum existing not one person knows how the single fan with no switch works. I've replaced my ECM, Fan Motor, CTS, Temp Sender, AC Low Pressure switch and fan Relay and the fan still doesn't work. My AC compressor comes on but the fan doesn't. How does it work?

 

The factory manual shows the fan controlled by the ECM, connector C2, terminal C1, is the trigger for the relay. The AC pressure switch feeds into the ECM to tell the ECM to control the fan. With all you replaced it sounds like wiring may be suspect.

 

Is Connector C2, terminal C1 on the back of the ECM?

Where is this AC Pressure switch? I keep seeing diagrams for one that has a dark green/white and black wire running to it. I know the low pressure switch on the back of the drier has a light green and blue wires running to it. Where is this other ac pressure switch?

 

I would suggest getting a factory service manual. I got mine off eBay inexpensively

 

I have one but I can't find the AC pressure switch with the dark green/white and black wire that's shown.

 

You need to learn to use your book then. My book says the Fan pressure switch is "lower RH rear of engine, on A/C line" and it shows on page 201-6-A. Looks like it is on the hard AC line that comes from the condensor.

 

You should start continuity testing wires all the way through. You probably have a bad wire or connection. Have you tested to make sure the fusable link hasn't burned up? Then test the other wires to the relay to make sure the wire isn't burne dor you have a bad connection

 

The problem is a lot of my wires are different colors compared to what the book says. They have definitely have been cut into and replaced. A good portion of my wires are white, black and brown instead of multicolored.

I'll check the book again and trace that hard line. Do you know what the fan pressure switch looks like? Is it this?
https://www.oreillyauto.com/detail/b...e+switch&pos=1

 

That's the switch that goes in the back of the R4 compressor.

Even if your colors don't match up you have to just use the book to find the "ends" of the wire. The colors are irrelevant if you just go from relay terminal A to Power, something like that.

If your wires aren't the correct colors it sounds like your connectors have been replaced which would mean that there are splices in the loom not far from the socket. If you don't want to continuity test wires you'll have to start pulling loom back and looking at the wires. You're going to have to start doing something, one or the other

 

This should be the switch
https://www.rockauto.com/en/catalog/...ch+switch,4284

 

What is this AC pressure that I am looking for? What is the part number?

Noob question but when doing continuity testing what am I looking for exactly on my multimeter? I've watched a bunch of YouTube videos on the subject but none of them explain what to look for or show the multimeter and it's readings. They just say set it to ohms and check for continuity. When I checked the relay it says -630 ohms.

I'll admit I'm an electrical noob.

 

You're looking for continuity. Many multimeters have a continuity test, it just beeps if the circuit has continuity all the way from probe to probe. If you're using ohms, you want to see as low a number as possible. 630 would be resistive, that was probably the control circuit for the relay. A normal wire circuit should probably be 50 ohms or less, probably be more like 10 or less

 

I can. Do you have any idea how many people don't even understand their own cars? Much less have a working knowledge of other year/model thirdgens? I've owned about a dozen thirdgens, of all different kinds, and read much of what is posted, spend hours with my nose in books, and I still make mistakes and admittedly have blind spots in my knowledge.

 

And this is where the mixed info. begins-"this is what it shows-this is what you have-read it." Welp, that is like mine. I've just been going through this myself, and when someone answers, and gives out (this so and so goes to so and so according to this book/thread/etc., they are giving just (1) of the many variations of that particular years wiring schematic. I have gotten my FSM. I have read my FSM. I have read these multiple conflicting threads where the person answering gets snide and down right arrogant that YOU don't know, and when it isn't making sense because they gave you the wrong information according to YOUR layout, that this seems to be the norm around here anymore. US noobs are trying to learn this, the same as anyone else had to before, so PLEASE be patient when we are asking legitimate questions. P.S. my stock 86 does not have this on my hard line, nor a switch on my power steering line (I know this wasn't referenced this time, but has in the past). I believe there was 3 actual routings of this on this year between carbed, F.I., and berlinettas. What you showed was only 1.

 

This is where you can get the wiring info without having to purchase a book.
86 camaro electrical
http://92b4crs.tripod.com/86wiring/86wiringindex.html

GL

 

That's the low pressure switch. So the Fan pressure switch and the low pressure switch are the same? I already replaced that.

 

The ECM controls the single fan with no head mounted switch. Case closed.

Probably not the 86 Schematic. I posted an 85 schematic in your other thread so you could see how the system was set-up and SPECIIFED that it was an 85 diagram. Did you ever look on the AC pressure line for a sensor ?? ( There's only 1 sensor on it ! )

BINGO !

I just posted this pic in another thread you guys are working thru in the ELECTRONICS forum,... THIS CAR IS AN 86 TPI. hope it helps.

 

OP, I saw this thread and your other thread. There is no lack of information. The real issue is you don't know how to troubleshoot and solve problems.

If you can bring somebody else into the discussion that has a better working knowledge of electrical then we can talk. It's just too frustrating (for me) to try to walk you through this problem because you won't understand. You need somebody to give you hands-on help in my opinion.

 

Bad wiring or a bad plug at any place in the system can/will cause problems with diagnosis so look over all plugs and plug terminals closely for burns, cracked wires, or bent terminals. Other things can also get in the way of diagnosis..... so these steps ASSUME an otherwise correct / functional electrical system.





Turn the key to RUN,

Check for power on PIN 'E 'and PIN 'C' at the relay. If there is no power on "E" the fusible link is suspect, fix and start again. If there is no power on C replace the fuse and start again.

Clip a long wire to body ground somewhere in the engine bay. Anything that's bare metal will do. You will need this wire to "JUMP" ground to the AC switch.
Have a voltmeter ready for use.

Ground the BLUE wire at the AC line sensor. Did the fans come on ??
If Yes: than the ECM, relay are fine and the pressure switch is suspect.

If No: than the ECM & relay and/or relay are suspect. ( AC switch not proven to be OK yet ):
Keep Blue wire grounded,.. check for ground at GREEN/WHITE wire @ PIN "B" on the relay: Is there ground ??
If Yes: than check for power at PIN "A" of relay. If no power than the replay is suspect. ( Again--- MUST check PINS 'E' & 'C' first to be sure relay is getting power from link and fuse.) If there is ground on GREEN/WHITE, and Power on 'E' & 'C' there should be power on 'A'; if still no power on 'A' the Relay is suspect.
If No: The ECM is suspect.

Disconnect ground from BLUE wire on AC switch.

Ground the GREEN/WHITE wire on the Relay. Does the fan work? ( Again--- MUST check PINS 'E' & 'C' first to be sure relay is getting power from link and fuse.)
If Yes: ECM is suspect
If No: Relay is suspect.

I think that's right,.... any/every one: please correct me if I'm wrong so future readers get the most accurate info possible.


Good luck !