a/c compressor to work on 24v

[trent]

Ed; So I make the connections and found #64 ,purple/gray and adding power/signal back to ecu with no help in idling . My c103 plug has both sides of the connector that was running into old ecu.This was cut off and left wild. I'm going to run power off aux fan for compressor until I can learn more about what's missing in my wiring. The second thing to unwind is the idle/ecu ,I do get the surgy idle at times and want this resolved! Any more ideas are great and It's off to pickn pull to look at a late e30 that I can take apart and not have to put back together. joe

What is this black/red wire supposed to do? Be a switched 12V when you hit the A/C I just went out and tested this wire and a/c on or off voltage didn't change.

TTT

[trent]

What is this black/red wire supposed to do? Be a switched 12V when you hit the A/C I just went out and tested this wire and a/c on or off voltage didn't change.

TTT

Ok, well, I just looked at the ETM for a late car (89 325i) and my early car 84 318.

On the 84 318, the purple wire that comes from the switch traces off and goes to the seperate idle control unit that these cars had (hope that makes sense).

On the later car 89 325i, it states the wire is a BK/VI which is black and violet.

Nowhere, in any of those diagrams does it show a black/red wire.

It took a bit for the DME to adjust to it's new input. 2 days later and it idles well enough that I don't have to heal/toe downshift coming to a stop or LFB in neutral to keep the R's up.

Not saying you are wrong, but in so few words, I "think" you are. The DME should not have to to adjust to a static signal that tells it to bump the idle. Yea, the idle will adjust, but it should be a noticeable couple hundred rpm bump with that input, not an ecu correction. These cars are not that advanced.

[ed94r]

Now that it's all buttoned up I'm not exactly sure what color the wires were. I believe in my minds eye that they were bk/rd..but I won't mortgage the house on it. I'm about 95% tho.

I was shown the book for a 3.something(3?) DME which had 64 as an A/C hot and 65 for A/C hi pressure. Additionally, I was told that the pigtail underdash contained an A/C hot signal/A/C hi press signal. I had them both spliced but the A/C pressure 65 caused a check engine code when A/C switch was defeated. Soo...I removed the 65 pin and kept the 64 wired to the bk/rd and it did the trick. It idled like shit and now it doesn't. I'm at a loss for further explanation. Sorry if I lead anyone down a dead end.

Ed

[croatan]

Page 93 of the e30 ETM, BK/RD wire @ C136 and BK/VI @ C136 on page 92.
There are two wires of these descriptions in the C136 connector on my 11/88 build 325i.

[croatan]

Ed, not necessarily a dead end but an avenue worth a look.

[Bmjpv]

a/c to work

So last time I was on the hunt to power up the a/c compersssor. I starting tracing to the compressor from the dash switch and than .... It started working ,gets cold ! WTF did I do? don't know and maybe never will. But for reference I have that v/gray and the b/red off ac switch,attached the two and tapped into #64 pink/gray. Idling is still a problem (returning to idle hunt) but it might be getting better?? This is getting to be no fun. 88' 325is, joe

OK I found my Idling problem !! I should have know better but overlooked the brake booster hoses and how tight they were on the fittings. It's all about basics and I overlooked one! Now it idles smoooooth and I love this thing. joe

[ericzz]

Before I go ahead and do this wiring can someone confirm it's terminal 64 on a 506 DME that gets the bk/rd wire offthe A/C switch pigtail 12v input thanks . The A/C is ice cold but the idle is erratic and it stalls at lights .

[catch22]

Sort of related question: Do you guys use the e30 or e36 condensor when installing the AC system in an e30/m50?

thnx

[ericzz]

Sort of related question: Do you guys use the e30 or e36 condensor when installing the AC system in an e30/m50?

thnx

I have an e30 condensor and an e36 z3 compressor . I did the hot wire blk/red to terminal 64 with no improvement ? I doulbe checked everything a few times no real change .On another note the A/C works very well very cold and quiet .

[catch22]

Could one use the e36 condenser though? I fubard my e30 condenser in the process of swapping the engine and i can perhaps get an e36 for cheap/free.. any idea?

[Mr.SWISS]

Damitt!!! :hitler:

Got my custom hoses today, new drier, flushed the sys and filled it. A\C barely gets cool, and it had the temp creep up to the 3rd line on the gauge ...ON THE DAMN HIGHWAY!!!!!ARRGH!#@%%$^ :letitout:

[djborya]

a/c preformance poor

What are your gauge readings??

[Mr.SWISS]

What are your gauge readings??

You mean the refrig ? I didn't use a gauge....



I had my old R-12 can tap and it fit the 134a can and screwed right on my fitting so I figured I'd save the $10 for fittings and have one less leak spot. I filled it till the high press switch kicked in and let some out till it released the high press switch. :???:

[DaN]

I think you guys are missing something regarding a/c compressor control.
The later e30 like my 90 has an evap temp module which controls the compressor.
The e36 dme gets an a/c request signal from the ihka, and then the DME activates the compressor by grounding a relay.

That is why no one is seeing a result when only hooking up the a/c on signal to the DME.
Looking at my diagram the a/c request comes into pin 65 of the DME, then the DME will adjust idle and ground the compressor relay from pin 48 (varies depending on dme).
So we need to add a compressor relay, or some how work with the e30 evap temp control while allowing the DME to do some controlling.

[hugh jass]

bump, anyone ever get this issue 100% resolved?