Need help with Crazy 968 electrical issue

[Mukilteo911]

Problem:
Power windows, fresh air blower and windshield wiper electrical failure. These all work or don't work at the same time. Some times the fresh air blower will be working and not the windows or wipers, then you try to turn on wipers and fan stops working, only to come on again later while driving.

I've been able to get them back on of off by slapping top of fuse block cover...

What I've done so far:
I've cleaned all the fuses to related parts, relays inside and out to remove any carbon deposits or gunk on terminals. Nothing inside relays was fried, carbon on contacts was minimal and easy to get off.

I pulled the fuse block up to have a look under and nothing was burnt or loose that was readily apparent.

Is there a master relay somewhere else or electrical component that all of these are tied too that is not in owners manual?

Any ideas on figuring this out?

Thanks in advance.

[JonA]

Are all your grounds clean?

Jon

[Mukilteo911]

Yep and if they were not, I'd expect the issues to carry through to other electronics.

Something has to be connected between these somewhere, like a master relay or something. Otherwise they would not be affecting one another.

Still searching for solution.

Thanks

[JonA]

Don't have a schematic for the 968 but I think you are on the right track. Look for something they all share in common. I'd look at that fuse block again. Where does it get power from?

Jon

[Mukilteo911]

Anyone else know?

[djnolan]

There are several separate leads to the positive battery terminal. There is the main cable and four smaller leads on the 944. I think these power separate sections of the fuse block.

[944 Ecology]

The most likely cause is a defective X relay (which is plugged into position 14 on the fuse block). To test to see if that might be the case, make a jumper from a piece of wire and two large electrical crimp connectors. Remove the relay and plug the wires into the positions marked 30 and 87. If that works, then the relay is defective and should be replaced.

[Mukilteo911]

And the winner is 944 Ecology!!!! ding ding ding. Thank you so much. I pulled it with the car having the issue, tried the jumper and worked. So I sanded the contacts on the relay and coated contacts with pro gold, put back in and works every time. Ordered new part just in case. Thank you.