Finally got the car out for a good afternoon drive. Hit some traffic on the way home temp gauge went almost in the red. Pulled over, fan is not coming.

Dual Fan setup. Wiring is same as stock, A/C disconnected. 180 degree thermo and a 180 degree fan switch.

So we are diagnosing the primary fan.

First off on my own swaped the secondary relay over to the primary and no change fan still isant coming on. Swapped Fan Motors and no change fan still isant coming. Also disconnected the pass side connector and grounded in to the chassis and the fan did not come on.

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Looking at my service manual which confuses the hell out of me: Page 6E3-C12-5

To test:

disconnect fan relay
ignition on
probe test D and E with test light on ground

Light came "On"

Next:

Ground diagnostic "test" terminal (what terminal is the ground? which terminal do i ground out???)
probe circuit 335(green/white) with a test light connected to 12 volts light should come on does it? ( Did this and light does not come on prolly cause i dont have a ground so what how do i do it?)


So thats where im at now, any help? If i skip that step and assume "Yes" the light came on next it says to jump A and E terminals together with a fused jumper and fan should run(Did this and no light)

Ya so i dont want to get to far of myself without testing stuff in order. So can someone tell me which terminal to ground out so i can test the green/white circuit?

Thanks
-Steve

 

Just went back to Page 1, i need to know where the Ground Diagnostic "Test" Terminal is...

 

Although I'm not sure where the Ground Diagnostic "Test" Terminal is I do have a few other points of view. does the fan come on when you turn the AC on? and have you tried powering the fans directly to make sure that the motors arent' burnt up?

 

No, the A/C is not hooked up. I have not tried powering the fans directly, whats the easiest way to go about that?

For all i know the fan may not have been working since last summer, this was the first time i have hit traffic in my car in a long time, so could any of this have happened after i removed the A/C from the car? I mean i dont think the primary fan is even connected to the A/C system at all.

 

I don't believe that the primary fan is connected to the AC either. I have seen people disconnect their AC and mess up their dual fan setup. but the easiest way to check the fan motor is to unplug the wiring from the fan, the run a power source directly to the 2 prongs right there where that plugged in. Running wires from the battery to the fan would probably be easiest.

 

Ya, will do.

Ill check both the motors tommaro.

 

I do believe (not 100%) but if you use the paperclip as you would read codes the comp controlled fan should run. The Diagnostic test terminal is the pin in the ALDL you ground to check codes.

 

Hey Stevo, hope I can help. If you are having problems with BOTH fans it is most likely a supply issue. Each fan is grounded through separate circuits- the primary thru the ECM only (via the chip and CTS) and secondary from the temp switch (and A/C pressure switch if optioned.)

You really should pick up a cheapo DigitalMultiMeter from Autozone or where ever, light testers are limited and inaccurate...

1. Please confirm that you are getting 10-12V on terminal E on each relay (other lead on engine/frame ground) which will be hot-at-all-times to quote Haynes LOL. If not you have a burnt fusible link off your battery or a short in your single pin weatherpak connector between the battery and fusible link (these like to melt and lose continuity... don't ask me how I know.) Also check your FAN fuse in your fuse block.

2. Unplug the fan motors and run engine up to "high" temp and check the plug for 12V with KeyOnEngineOff (other lead on engine/frame ground.) You MAY need a paper clip to get a reading depending on the DMM leads- BE CAREFUL! If you do have 12v there, Ohm out the two terminals on each motor. You should get a low Ohm reading- I'm guessing less than 20 or so... I would have to check mine to confirm with you. If you get a VERY high reading the motor is shot. I would not recommend using a separate power source to check your fans.

3. If they check good and you do not get 12V at the plug, run your engine to high temp (the point that the fans would come on- KOEO) and check your Ohms from terminal F on both relays to ground. Should get .4 or less depending on the DMM. If VERY high reading Ohm reading (OL)...

Primary relay- you have an ECM/CTS/chip/wiring issue. Usually have check engine light.
Secondary relay- you have a defective temp switch in your passenger side head/ shorted connector or wiring issue.

4. If you do not get 12V at the motor plugs but DO get a good reading on terminal F, check voltage at pin D on each relay (at "high" temp- KOEO) (other lead on engine/frame ground) you should have 12 V supply from fuse block to the relay coil.

That's everything off the top of my head. Keep us posted and be sure to ask questions. Good Luck!

 

Awesome reply. Thanks a lot. Im about to get out there now and start testing some stuff out.

I do have a multimeter, just then manual never told me when i needed it. When you say 10-12volts off terminal E do you want to me poke the wire in the center with the relay still attached or do you mean to test the relay connector?

Also The Fan fuse the only one im away of is under the dash is that the correct fuse? If so its 20 amp and its good. I do want to find the fuseable link coming off the battery and have a look.

One thing i did remember which happened yesterday. I had the valve cover off and when i went to put it back on i accidently touched the back positive terminal of the alternator to the cylinder head, sparked a lot luckily i wasnt shocked. Then disconnected the batter and reconnected it, didnt seem to short anything out.

But anyway im up early to get an early start on this id like to get to a car show tonight and have a fan if i hit any traffic!

-Steve

 

Alright well here goes:

1. I am getting 11 volts to both Terminal E Orange wires at the relays.

2. Ran the car high and checked the fan plug connectors The primary fan im getting nothing...no reading coming up at all. Checking the secondary fan plug im getting steady 6.8 then sometimes going up to a steady 11.7 volts.

3. Checked Terminals F at both relays. Primary is way up around 140ohms! Jumping around very high. Terminal F for the secondary fan is around 4 ohms, and keeping lower.

4. Checked Terminal D for both fans (brown ignition wire) and am getting 13 volts so thats a pass.

So i think we are getting somewhere...sounds like the primary fan is screwed up. How the hell do i trace the green/white wire back to the computer?

Whats next for me to do?

 

Ok just an update. Fixed the problem, i had shorted out the fuseable link for the secondary fan. Very confused though.

The fan closest to the battery is the fan that runs all the time and the fan on the driver side is for A/C?

Anyway im completely messed up cause the grey wire fan relay says its for the secondary which is run for the A/C correct?

If so that is the fan that is working now, it runs once the car hits 180 or whatever the fan switch i installed was. But clearly tested it and when i ground out the fan switch wire it sends voltage to that fan.

Anyway what im doing is im going to run the other fan which i guess i dont use anymore because no a/c to a toggle switch in the interior.

 

The seconday fan has the grey wire for the relay- grounded by the A/C switch and/or temp switch. I removed my A/C and both fans still work as normal.

The primary fan has the green/white wire from the ECM. I would first double check all grounds, make sure that are all TIGHT. Second I would look for that wire going into the ECM (I wish I could tell ya what pin #) and ensure it has a good tight connection. Are you getting any SES codes? Any new proms lately?

A great link for the diagram: https://www.thirdgen.org/forums/elec...ht=primary+fan

The manual switch is OK, just don't forget to turn it on or like I did... let the GF drive it.

 

No codes, no different proms.

So what triggers the primary fan, the green/white fan relay. I thought that ran off of the temp switch in the passenger side head and the secondary fan grey fan relay ran off of the a/c pressure switch.

 

The primary runs only off of the ECM. The secondary runs off the temp switch in series with the A/C pressure switch if equipped.

 

well i looked threw my engine bay and i found one connecter that was unpluged on the a/c one with two prongs it will connect either way how do i kno which is the right way?

 

I don't think it will matter because it is just a switch to connect both wires togeather.
Here is a link to a Wiring diagram for youre moddel, maby it will help you:
http://www.austinthirdgen.org/module...ine_wiring.gif