Jumping the Cooler fan relay

douglas bray · 08:26 PM

Merry Christmas everyone.

It just dawned on me that my oil cooler fan isn't working. It was one of the "I'll get to it" things to do. Now, stuck at my mother-in-law's house tonight I'm worried about tomorrow.

First thing in the morning we are getting in my '88 Carrera and heading 4 hours up the coast to Pismo Beach. It's the drive home sunday light that has me worried.

I installed a new OEM fan on my oil cooler and pluged it right back in just as the original came. Only thing is that it didn't ever turn on. I'm assuming at this point that either the relay or the thermo-switch is bad.

I have almost no time in the morning to figure out the exact problem and fix it. So, against all logic and reason let me pose a question:

Can I just jump the relay? If I identify the correct relay and remove it can I just bypass it ?

I promise to do it right when the weekend is over and for sure before I join you guys for the drive up to julian on new years day.

Here is the scematic I found that makes it look easy:
Location for Switch

It looks like I can jump from 87 to 30 or 86. No?

douglas bray · 08:32 PM

Will I also have to gound out 85?

fintstone · fintstone's Garage

Front fender Oil Cooler Question

douglas bray · 12-25-2009, 09:51 PM

Quote:

Originally Posted by fintstone

Front fender Oil Cooler Question

Thank you very much. I just drove home. I'm headed out to the shed to have a look.

fintstone · fintstone's Garage

Make sure you check the fuses first. One of those is likely the problem

Assuming the problem is not the lack of ground...removing the relay and jumping from pin 30 to 87 should make the fan run continuously.

douglas bray · 10:48 PM

Quote:

Originally Posted by fintstone

Make sure you check the fuses first. One of those is likely the problem

Assuming the problem is not the lack of ground...removing the relay and jumping from pin 30 to 87 should make the fan run continuously.

Dude, you are awesome. All it took was a quick read through your instructions and a sacrificial section of wire and she was off to the races. That baby can push some air.

So....We now know that it is the thermo-switch that is in need of replacing. That is ok 'cause when I did the fan the foam perimeter didn't arrive in time and is still sitting on the shelf. I'll get the new switch and do the foam install at the same time. Now if I could just remember the BMW part# for the one that comes on sooner.

Now to go out and enjoy setting #3 on my new Russell Berry Multi-board.

fintstone · fintstone's Garage

No problem. Merry Christmas.

mthomas58 · 12-26-2009, 04:48 AM

Quote:

Originally Posted by douglas bray

Dude, you are awesome. All it took was a quick read through your instructions and a sacrificial section of wire and she was off to the races. That baby can push some air.

So....We now know that it is the thermo-switch that is in need of replacing. That is ok 'cause when I did the fan the foam perimeter didn't arrive in time and is still sitting on the shelf. I'll get the new switch and do the foam install at the same time. Now if I could just remember the BMW part# for the one that comes on sooner.

Now to go out and enjoy setting #3 on my new Russell Berry Multi-board.

The BMW part # is located at post #7 on this thread:

oil cooler fan t'stat and switch installation

Lots of information on adding, locating and wiring a manual over-ride switch here:

Remote cooling fan ''switch"?

douglas bray · 12-27-2009, 08:40 PM

Quote:

Originally Posted by mthomas58

The BMW part # is located at post #7 on this thread:

oil cooler fan t'stat and switch installation

Lots of information on adding, locating and wiring a manual over-ride switch here:

Remote cooling fan ''switch"?

Again, you are awesome. We put 477.6 miles on the car this weekend and never once saw the temp more than a smidge past the second mark.

I pulled in the driveway and the gas light came on. I'm sure I could have squeeked out 500 miles had I just not had so much fun>

EmeraldE · 08-08-2010, 03:50 PM

My '77 C 3.0 is wired for headlight washers, which I won't use but I do want to connect an OEM fan for an OEM radiator oil cooler that I am installing. The wiring for the headlight washers is very accessible in the front of the trunk, but I'm not sure if the wiring is sufficient? It runs through a 16 amp fuse, and I believe it has a separate relay but have not confirmed that yet - my Bentleys shows a relay for the '81-83 headlight washer, but doesn't indicate for '77.

Has anyone used this approach? My alternative is to install wiring as described in this thread and use the existing rear wiper switch (the rear wiper is AWOL).

Thanks for any help.