electric fans/ac inop

Topic: electric fans/ac inop (Read 5921 times) previous topic - next topic

electric fans/ac inop

July 23, 2011, 06:07:58 PM

lemme start over...
My TC has an aftermarket fan control thingy that tapped into both the cooling fans. It has an adjustable thermostat, and would keep the fans running til the radiator cooled...sorta like a turbo timer. Well it was draining the battery so I took it all off and reconnected the 2 cooling fans wiring back to factory. Now the fans and AC are both inop. I ran the fan troubleshooting guide at NATO and the original IRCM wasnt working so I swapped it out. I then ran the test again and both fans worked, which means the wiring is fine all the way to the EEC(according to the NATO article). But, it still ran hot. So then I replaced the ECT. Still no good.
I then found fuse 17 blown, so I disconnected the speed control module and the rear defrost connector on the temp control panel, replaced the fuse, and started the car. As soon as I moved the lever to max ac...bam, the fuse popped. This time I disconnected the connectors at the cycling switch, AC compressor and high pressure switch, replaced the fuse and started it up. This time the fuse is good. I slowly hooked one connector up at a time, cranked it up, moved the lever to every position, and the fuse held each time. Now everything is hooked back up, the fuse held, but I still am not getting the AC or fans to work.
When I turn the key to on, the passenger fan comes on for a second like normal...other than that I just dont know. I am guessing the aftermarket system may have been installed to bypass the original problem? Dunno. Does the IRCM have any control over the AC? Also, aren't the fans supposed to come on when you select A/C?
FYI, this car has a manual temp controller.

electric fans/ac inop

Reply #1 – July 24, 2011, 02:15:40 AM

Quote from: lakenheath24;363889

Everything worked, but I removed the fan portion of the system, cuz it was draining the battery(it wouldnt shut off sometimes). Now the fans wont come on when it gets hot and the AC wont come on.

I hope that was a typo cause other wise you just answered your own question lol.

If you have access to a good IRCM I would try that first. Those things can cause weird problems sometimes, and it is possible that the one you put it already has something wrong with it.

Also, or you SURE you spliced the wires back like stock? If you accidentally got a pair backwards, that could also definitely cause this kinda problem...

electric fans/ac inop

Reply #2 – July 24, 2011, 09:32:48 AM

I removed the fan portion of the alarm system. It spliced into the stock fan wiring. The fans work...they just don't come on when it gets hot.

electric fans/ac inop

Reply #3 – July 24, 2011, 09:53:22 AM

I don't understand why fans and alarm systems would have anything to do with each other. Somebody else is gonna have to help you out here sorry

electric fans/ac inop

Reply #4 – July 24, 2011, 10:56:26 AM

disregard the alarm part...I was just giving some background. I found fuse 17 blown. I replaced it and it blew again. This one controls a ton...including the a/c clutch. Could be a reason why an aftermarket fan controller was installed. Guess I'll be chasing down a lot of wires.

Not my cup of tea.

electric fans/ac inop

Reply #5 – July 24, 2011, 12:19:27 PM

Looking at the fuse 17 circuit, I unplugged the speed controller and the rear defrost connector. I then started the car....moved the lever to a/c and, wham, the fuse blew. this is gonna suck.

electric fans/ac inop

Reply #6 – July 24, 2011, 03:01:41 PM

You should backtrack your wiring from the ac compressor backwards. Its easy for the wiring to get pinched or smashed in something so its probably shorted or grounded to the frame causing the fuse to blow. I had a very similar situation once. I had to cut out and replace a damaged section of wiring cause it had come loose and gotten shredded somehow.

electric fans/ac inop

Reply #7 – July 24, 2011, 03:28:39 PM

i rewrote the OP...lemme know if that's any clearer.

electric fans/ac inop

Reply #8 – July 24, 2011, 03:46:06 PM

Well that makes more sense. The IRCM does have some control over the AC since it has to turn the fans on to pull air through the condenser. If the engine is below the necessary temp but the ac is on, it has to turn the fans on, so yes, the fans should come on when you put the switch on. This is why I was saying it could be your IRCM. The other thing I was saying is that if your fuse only blew with the ac turned on and everything else disconnected, then your problem is almost definitely somewhere in the compressor circuit. Unless you just got to bad fuses... but it could also be the case, that if something is shorting out in your IRCM that could also cause the fuse to blow. The problem in the IRCM may not always present itself. They're tricky little buggers sometimes.

electric fans/ac inop

Reply #9 – July 25, 2011, 03:57:00 PM

Remove the connector from the AC clutch and replace the fuse and turn on the AC. If it blows again do the same with the blower circuit unless the heater works ok with the fan. Process of elimination is the key to electrical problems. Check all the components controlled by the fuse that blows. I have found many AC clutch coils draw way to much current and blow fuses. Good luck

electric fans/ac inop

Reply #10 – July 26, 2011, 07:00:56 PM

well I have tried THREE IRCM's and still no good. The EVTM is a bit confusing. Pg 234 is a test for the control switch, but there is no listing for a c276, so I aint sure where that is. I tested the clutch coil, pressure switch on the accumulator, and even tested the diode...all are good.(pg 104 evtm) On pg 65 of the evtm...it shows a fan/control a/c pressure switch...does anyone know which one that is? There doesnt seem to be a test for that one.
Again...FYI, I did the fan test IAW NATO instructions and both fans come on. Is there a point where the 2 systems(a/c and engine temp) come together? I may just have the stereo peeps rig up a bypass like was on it.

electric fans/ac inop

Reply #11 – July 26, 2011, 07:01:11 PM

electric fans/ac inop

Reply #12 – July 27, 2011, 05:35:02 PM

My interpretation of the IRCM (integrated controller module) from studying the 87 EVTM.
1. The LG/P wire to the top of the Compressor Cycling Pressure Switch is 12v from fuse 17 and the dash function selector switch being in A/C.
2. The solid state block is the equivalent of the WOT cutout relay. The red wire off the page to the right of the block goes to EEC pin 54, ground at WOT.
3. Without WOT there is 12v out the bottom of the solid state block to the BK/Y wire.
4. The BK/Y wire goes to the A/C compressor clutch and to EEC pin 10. Pin 10 signals the EEC that the A/C is on.
5. Ground on the PK wire on the bottom of the secondary EDF relay will put 12v on the BR/O wire to the secondary fan. The ground is from EEC pin 52 or the Fan Control A/C Pressure Switch.
6. Voltage (not ground) on the T/O wire from EEC pin 55 to the voltage inverter below primary EDF relay will put 12v on the BR/Y wire to the primary fan.

electric fans/ac inop

Reply #13 – July 27, 2011, 07:00:27 PM

Do you get a KOER code 21 after the engine is warmed up?

electric fans/ac inop

Reply #14 – July 27, 2011, 08:42:50 PM

I didnt get a code, but then again I ran the test cold, just to see if the main fan came on, which it did. Everything worked fine till I pulled the aftermarket fan control mess off, so I think it was put on to bypass a problem. I am looking at the component location (pg 105) and noticed the ECA. That's the blue plastic box on the right side of the dash right? Do you know what that does? The EVTM doesnt explain it.