AC and Electric Fan wiring help please!

[SpecM]

-My fan clutch went out so I ditched my engine driven fan and the entire AC system back to the firewall while I was at it...

-Here's my little predicament: I would like to reinstall my stock electric fan and use the factory plug for that. But when I push the AC button to turn on the fan, the idle bumps up, despite the fact that there is no AC compressor. So, how can I deactivate this and still be able to use my electric fan? I know that it will kick on if the car gets stupid hot but I would like to turn it on before that. And the idle bumping up to compensate for the nonexistant compresser wouldn't really help my hypothetical overheating problem...

-I say "hypothetical" because the car hasn't overheated since I did this about three weeks ago AND I want to make sure it doesn't. It will be spring soon!

-So who has AC system and electric fan wiring schematics so I can figure this out? Any help appretiated fellas.

-Yeah yeah I know fuh raze...

[Beej '86 325es]

I tried this a few years ago as well. I tried disconnecting all of the wires going to the A/C button, and none of them lowered the idle when disconnecting them. If anyone else knows, please share!

I'm going to try and cut the A/C core away from my fan to get some better flow to the radiator though...

[SpecM]

-Perhaps some connetion to the ICV module?

[turnofftheradio]

-Perhaps some connetion to the ICV module?

yes. there is a 1 wire input for this. I "think" it is a brown or black wire. The diagram is in the bentley. you will find the unit next to your ecu. usually a small green or black box (if it is black you have a crappy module) with 12? wires going into it

[SpecM]

-And this will not hurt the ICV unit, just not let it bump up the idle for the AC, right?

[arsevader]

yes. there is a 1 wire input for this. I "think" it is a brown or black wire. The diagram is in the bentley. you will find the unit next to your ecu. usually a small green or black box (if it is black you have a crappy module) with 12? wires going into it

Does the 1988 325 has this box? I thought they got rid of the ICM in 1987. Later models used the ECU to control ICV.

James

[turnofftheradio]

I believe all of the eta's continued to use the icv/icm until the end. but I'm not 100% on that...

I believe there was actually some bulletin about a poor idle and cutting the a/c wire to the icm. I can't for the life of me remember where I read that.

basically I am not much help.

[SpecM]

-I just did it! Its the purple/black wire going to the black connector under the ECU. No more idle bump!
-Now, I tried to connect my electric fan to test that, and it doesn't come on. Shouldn't it if the AC button is pressed? Man, it never ends

[turnofftheradio]

my a/c came in a seperate box :) I never put it on, so I'm not sure

[SpecM]

-OK OK I tested the fan with a 12v supply and it still doesn't work, so the fan may be toast. I'm getting 3 ohms of resistance (with no resistor) across it, is that normal?

[SpecM]

-Problem solved! I had removed the fan resistor, it was toast, and the higher power lever on the 'low' speed power feed poped the low-speed fuse. Replaced with a 30 amp fuse and she works!

-OK, OK. She's mounted and works fine. Just one qwibble... when I press the AC button to turn on the fan now, the idle DROPS, just a little like 50-100 rpm, but I swair it drops. Why?

-I've dissconnected the purplre/blk wire to cut the idle bump-up. The drop doesn't bother me, as long as the DME isn't modifying fuel or spark, cuz it's not the idle it's changing. I unplugged the ICV and manually set the idle to about 1000, pressed the button, and it still drops.

-Electric load on the alternator? Odd airflow to the air intake? Whaaa?

[SpecM]

-Bump

[turnofftheradio]

It may be alt. load, but I would think the icv would compensate after a sec.

just how low does it go?

[SpecM]

-Not that low. It drops about 50-100 rpm, down to say... 5-700 rpm? Like I said, it doesn't bother me, it is just strange.