Coolant Fan wiring - PO got me good - help

juVius · 12-22-2007, 12:45 PM

i've been trying to figure out why my coolant fans and heater blower aren't working. Thanks to Razorback1980's, mattdavis11's, myskyon's, and BrianT's help in a previous post, i was able to find this wiring problem in the picture below. does anyone know why the PO would have done this in the first place? was there a method to his madness? in the picture you can see where the green/yellow wire from the coolant fan relay was cut, spliced and rerouted to the a/c relay. now, since that wire is on the a/c relay, what wire is supposed to be on that pin for the a/c relay or was nothing there to begin with? any help would be greatly appreciated.

Britwrench · 12-22-2007, 12:52 PM

People do weird things, trace the wiring back and see what they connect to. Does the ac actually do anything?

By the way, you should replace the original DME relay.

juVius · 01:10 PM

Quote:

Originally Posted by Britwrench

People do weird things, trace the wiring back and see what they connect to. Does the ac actually do anything?

By the way, you should replace the original DME relay.

thanks. i'll have to dig my way through that pile of wires and check it out. i carry two spares in my glove box. are the newer ones designed better?

oh.. the a/c actually comes on, but the coolant fans do not while the a/c is on.

thanks again

mattdavis11 · 12-22-2007, 01:47 PM

The green yellow wire needs to be attached where it's supposed to be on the cooling fan relay. The more I look at your picture, it looks like he tied into the the fresh air fan relay. Do you have a cut red wire under there? The more I think about it, that is not the A/C relay in spot # 3 at all, i don't think. If he was to tie that splice into the black violet wire it might have worked, but I don't see that relay getting power how it is. Trace a red wire from fuse #9 and see if it has been cut, if it has splice it to terminal 30 on that relay. That relay, #3, only has 4 prongs right? 30, 85, 86, and 87? The A/C relay and cooling fan relays are 6 prong.

Did you look at the two relays on the passengers side?
Another ?, when you turn the a/c on, does the air box close a door? You will see it if you look to the right of the gas pedal, on the box.

The reason your a/c fans aren't coming on is most likely because the relay on the other side of the car is bad. Mine was.

I'm going to check out my car to see if I can get a better sense of what's supposed to be going on, the diagrams playing with me right now. Splice that wire back first, we'll go from there.

juVius · 12-22-2007, 01:59 PM

Quote:

Originally Posted by mattdavis11

The reason your a/c fans aren't coming on is most likely because the relay on the other side of the car is bad. Mine was.

i'll go out an put the wire the way it's supposed to be right now and check to see how many prongs are on relay number 3. as far as the a/c fans... it does blow, but i was under the impression that when the a/c is turned on the coolant fans are supposed to turn on also.

thanks again... i'll get back to you in a second...

Britwrench · 12-22-2007, 02:11 PM

With the ac on, the right side cooling fan comes on too.

Spare DME relay, the later ones, and they have been out for many years are better.
No reason to have the "it will fail, usually at the most inconvenient time" old style in the car.

mattdavis11 · 02:22 PM

Ok, I can't see squat with out removing all that stuff.

You are correct, the cooling fans come on full speed when the a/c is on, if everything is working how it's supposed to. Mine acted the same as yours until I replaced the relay on the passengers side. However, my fresh air blower worked, and my cooling fans came on when they were supposed to.

If that relay is the fresh air fan, which I think it is, we are one step closer to knocking out two of your problems. The wires going into the back of #3 would then be black/violet to 86, red to 30 (main off of fuse 9), red out of 87 to fresh air blower, and brown/yellow 85 to the fresh air blower interlock relay (opposite side of car with A/C relay). The fresh air interlock relay closes the blend door when the a/c is on, among other things.

Check to see if that's right.

juVius · 12-22-2007, 02:34 PM

ok... the green and yellow connection is repaired. i couldn't find a cut red wire floating around. the #3 relay has 5 terminals. i let the car heat up again just now to just below the yellow and they still didn't kick on.

juVius · 12-22-2007, 02:42 PM

here's another picture so you can see the wire colors on the #3 relay. which relay do you think that really is?

mattdavis11 · 12-22-2007, 02:59 PM

You already replaced the thermofan switch on the radiator, right? If not, jump the wires with a paper clip, don't let it ground though. You don't even have to have the motor on, or hot. If that doesn't work, test for power going into the relay #1, that would be the red/brown wire going into the back of the relay or terminal 30. That source of power is from fuse 3, another power source for that relay is from fuse 5 a yellow/black wire or terminal A.

Later we'll work on relay 3, but i think all the books (including factory) have it wrong. The reason I say that is because the a/c relay has no brown/yellow going to it per the diagrams, and I see a brown/yellow going to it.

mattdavis11 · 12-22-2007, 03:01 PM

That is in fact the fresh air fan relay. We have cracked something the Germans have misprinted time and again. Great job, now have a beer with me to celebrate.

juVius · 12-22-2007, 03:11 PM

i'll have to jump the thermofan switch in a few... she just used it to run up town to grab some chinese food.... while i'm waiting for her to get back, what wire should be going into #3 where the green and yellow wire used to be?

thanks again

mattdavis11 · 12-22-2007, 03:20 PM

I'm not seeing yellow/black going to the #1 relay. Is it there? Also, did the PO cut out the resistor that goes into the back of the relay? It would be further up the red/yellow wire. What it does is come off of fuse 3 as red, it splits into 2solid red goes to the resistor and comes out red/yellow and joins red/black at the relay, the half of the split is red/brown and is the main power. Red/Brown should be hot.

mattdavis11 · 03:33 PM

Quote:

Originally Posted by juVius

i'll have to jump the thermofan switch in a few... she just used it to run up town to grab some chinese food.... while i'm waiting for her to get back, what wire should be going into #3 where the green and yellow wire used to be?

thanks again

The red wire either comes off of fuse 9 and goes to that cut wire, or that cut wire goes to your fresh air fan, which is in the center under the hood below the windshield under the squirel cage. I think I can see it right there in your last picture, cut and all.

That was confusing I bet. It does one of two things, it powers the relay (from fuse 9) or it goes to your fan.

juVius · 12-22-2007, 03:51 PM

the yellow/black wire is there... i followed the red/yellow wire from the relay all the way to the wire duct that goes to the aux fuse panel. i didn't see a resister, but i didn't see any cuts either. i jump the thermofan switch and nothing happened.

juVius · 12-22-2007, 03:56 PM

oh.. the yellow/black and red/brown wire both have power to them.

juVius · 12-22-2007, 04:02 PM

i also connected the red wires back together on relay 3. there is no power to it both key on and off.

BrianT · 12-22-2007, 04:27 PM

I see the other end of the red wire hiding in the bundle.

I had some wiring dolts work on my car before I got it. First the fans ran all the time that the key was on. I was lucky, they took a better choice. They ran a wire from the fans and spliced into the wiring harness at the fire wall, that was a easy find, yours would take a lot of work just to find their screw up just to get started finding what the real problem is. They also had a button on the dash to start it with. I took this all off and then trouble shot why these things did not work, found what the real problem was, it was the ignition switch bad. They did all of that and all it was, was a 35.00 part. After you get the wiring back where it should be, you may want to check your ignition switch. Just food for thought.

mattdavis11 · 12-22-2007, 04:28 PM

We are working on relay #1. You should be able to jump yellow/black to green/yellow with the thermo fan switch still jumped and the right fan should come on. Try that, but not for long. You should also be able to jump red/brown to red/black and the left fan should come on.

On relay #3, I wasn't sure which red wire would have power, one of the two should.

Let me know, we'll get it straight.

That's what I saw as well Brian, I think that goes from the relay to the fresh air fan.

juVius · 12-22-2007, 04:42 PM

thanks briant... as luck would have it.. i ordered a new ignition switch 2 days ago... just waiting for it to come in...