Dick964

Maybe a question for the electricians amongs us:

I know the Oil Cooler Fan Override Switch from the DIY site (great site by the way...). In this DIY guide cutting a green/black wire on the back of your CCU is mentioned as "a trick" to install a manual switch.

I also read that disconnecting the plug from the oil temperature sender (mounted in the oil cooler in the front) will also start the the oil cooler fan blowing at high speed. Since I do not want to cut the wire at the back of my CCU, my question is if somebody ever tried to cut a wire at the temperature sender and re-routed this cable to the interior and installed a switch to start the fan.

Is this also a possible- and safe way to create a manual override switch?
Please advise.

Kind regards,

Dick964

911URGE

From the P-car DIY Fan section and go to the "Known Successful Repairs". There is a schematic on creating a jumper from the relay to start the low speed fan. Add a switch to this modification and that should do the trick.

Turbohead

I have done that it works fine.

tbennett017

I did the wire #12 mod behind the dashboard... a switch breaks the connection, causing the system to think the temp sensor has failed... causing the fan to run on high. Works great. Not so scary to do.

Dick964

Hello,

Thanks for your reactions.

@ 911URGE: Yes, I saw it but I do not understand it (not an electrician....)

@thennett017: Is this wire #12 another wire than the one mentioned behind the CCU ?

Rgds,

Dick

tbennett017

#12 is the wire behind the CCU.. more appropriately it is th G12 wire (but do confirm that before you proceed) I found a long length of it in the wiring and just cut a switch into that line, soldering the connections and using shrink wrap etc....I am not crazy about cutting original wiring either, but it seems like the quickest solution. I mounted a simple switch on a bracket just above the lower console, running the wiring under the carpet etc... all nice and neat. I can send pix if you need.. PM me..

There are many DIY's on doing this on here and p-car.com.

Dick964

Thanks Thennett. Pics are not needed but thank you very much anyway.

In the DIY story I read the G12 is a green/black wire.
Can somebody confirm if this green/black wire is the only one with that colours at the back of the CCU ?

Why I am asking ? I am a bit scared to disconnect the connectors at the back of the CCU. I am afraid that connectors will break or wire snaps loose from the connector...
I rather sort this wire out without disconnecting the connectors...

Thanks,

Dick964

tbennett017

Dick,

In my experience, the connectors aren't too bad. I know what you mean.. a lot of the electrical connectors from the 90s were a real bear to get apart.. requiring a lot of pulling and force. And I do understand that the temp control unit is an expensive item to replace... but those smartypants germans designed the big plug to be pretty easy to remove, with a metal cam/lock mechanism. As you lift the metal lock, the connectors just come apart easily. When I did the G12 thing it was a no-brainer, and by far one of the easier parts of the job.

Looking at the back of one of the connectors, it is a simple matter of counting over to confirm. The plug has (IIRC) tiny numbers and digits in the corners, to give you a starting point. G in one end and something like 1-12 on the top and 13-24 on the bottom (?) Anyway, it will be a simple matter to count over to G12 and confirm it is the black/green (or green/black- sorry to not have my facts at hand here...)

You can probably do the job without removing the plug.. but it really will make it easier...and might even be safer for the little CPU as you are not then bending and manipulating the back of the box itself so much.

Just my 2 deutshmark.

Dick964

OK, good information.
I am quite sure now I will try the CCU way...

Thank you all for the information

Kind regards,

Dick964