waveflux

...while unplugging the unit, the prongs came out of the black plastic caps.
Soooo....I need to match proper color with proper number.

1989 s4
part# 928 618 418 00

stage I connections number 1 thru 8
stage II connections number 1 thru 8

Wire colors
Red
black
green
blue
green/white
black/white
brown/black

Brown
Gray
green/gray
brown/green
red/white
blue/green
brown/blue

Thanks for playing!

ammonman

I couldn’t read the color labels on my 1989 wiring diagrams, but the list below is from my 1990 S4. I pulled the plugs and verified each wire versus the terminal number on the plug body. Hope this helps.

Mike

Plug I
1=Green/White
2=Red
3=blank
4=Black
5=White/Black
6=Blue
7=Brown/Black
8=Green

Plug II
1=Blue/Green
2=White/Red
3=Brown/Blue
4=Brown/Gray
5=Green/Gray
6=Brown/Green
7=Gray
8=blank

waveflux

Ding, Ding, Ding, I think we have a winner!


I'll plug and play tomorrow. Thanks!

waveflux

Problem: Both cooling fans not working.
Fuses good.
Jumped the fans, both worked.
Cleaned and secured battery connections (nope)
Checked Fan controller by seat before moving to Amplifier under the hood.
Controller was bad.
Picked up one on Fleabay for $49
Screwed up the wiring sequence during install
Membership has it's privileges ( see above)
Both fans are working
Huzzah!

ammonman

Excellent. Glad to help.

Mike

westija

Waveflux,

My '89 928 S4 had the fans running at full speed always. Followed some threads and found that previous owner had the Transducer disconnected from the bottom of the radiator. Once I connected now my fans run at half speed when I turn the engine on (still cold).
I am suspectimng it might be the Fan Control unit between passenger seat and door under the cover. Do you mind sharing how you troubleshot that?

By the way, I am in Weston, pretty close to Fort Lauderdale.

Thanks
Jose

Big Easy Sharkster

I have a similar problem.. one fan runs (driver side), but not the other. Mostly on high spd. Did a search and all seemed to point towards the Final Stage Output (928 618 421 00). Got lazy and bought the unit without checking the other parts (jumping the fans and checking controller). Installed the unit, but did not fix the problem. So, I got that going for me.

However, I've developed a strange noise in the passenger compartment, and I believe this noise has something to do with this fan problem because both started about the same time. When I do a moderate or hard brake, or when I hit a bump in the road, I'll get a noise in the cockpit (sounds like from behind the dash, but can't confirm) that sounds like the clicking noise ball bearings make when rolling around and they contact each other.

Any ideas what this is?

rgs944

Thread revival, Does anyone have a picture of the control module by the seat. I have one fan not working. Fuses are good and the non working fan works when I switch the wires.

rgs944

One more question. I went to 928's specialist website and read through the troubleshooting of the fans. What is the "fan output stage" they are reffering to.

Big Easy Sharkster

#16 is the Final Stage Output

rgs944

Thank you, that's what I needed.

rgs944

Is the final stage output a likely failure point. My situation might not be typical. Here is what happened. I noticed the passenger fan was not working. After inspection it could not work because it was hung up on a hose routed wrong. So you would think that would blow a fuse. Fuse is good so it either burnt a wire somewhere or created a short in the F I stage unit or contoller.

dr bob

Check the fuses and the holders in situ: Use a voltmeter with a thin probe that will poke into the back of the fuse itself. Short the two wires in the intake temp sensor (brown and brown/green IIRC) together, and tape the hood switch so the fans will run on low. You should see battery voltage on both sides of both fuses (28 and 29), referenced to ground. If all is OK, pull the fuses and inspect the sockets for melting. If you didn't see battery voltage, inspect the fuses themselves. If they are OK, work back towards the battery connections, the little accessory red wires at the battery positive terminal. Try this before you spend on new controller and final stages module.

Big Easy Sharkster

I'd listen to Dr Bob abd the other 'pros' that know this stuff better than me, but my problem was the passenger fan stopped working and the driver's side ran on high. Visually checked the fuses (note 'visually') and all OK. I read all the posts I could find and deducted that it was the fan output stage (or final stage output) was defective. Probably should have run other tests 1st, but I just went and ordered a rebuilt unit, Installed it and still had the problem. Inspected the fuses, pulled them (they were OK) and reinstalled with new fuses. Both fans now ran as designed.

I went and replaced all fuses on the electrical panel that day with new fuses.