Sab

This has been plaguing me for some time now and since the weather is getting hot again the car starts to get hot in traffic again.

It is the passenger fan and it seems it goes on strike once the weather gets hot, it works fine everytime I check when it's cool out.

1. The fan runs strong when I wire it directly to a battery. So I assume it is not the fan itself.

2. It is intermittent, so it is hard to check, but I was able to reproduce it once at home and had no power on the connector that goes to that fan, while the other fan was blowing.

3. My controller in the front is new and I swapped it and the fan controller module by the seat with Cameron's controllers. There was no change on either cars after the swap on either car.

4. I reseated the fuses, swapped the fuses, no change.

What should I use to clean all connectors in the fuse panel?

My guess it is the cabling. How can I bypass the cabling from the fan to the fuse panel?

Can I steal power somewhere in the front to wire it to always run for now?

I don't want to blow a motor in rush hour for this seemingly minor problem...

Please someone help me out with this one.
Thanks,

Mike Frye

I think the new DR dual fan is set up to be wired from the jump post for positive and a chassis ground, the circuit has a thermostat that sticks in between some part of the radiator. This way it kicks in when the radiator is above a certain temp.

You could get a thermo switch like this and wire it permanantly, no?

dr bob

Sab--

Go into the battery well and clean the connections there to the positive cable. The two fans each have a dedicated power feed that runs from the battery to the fuse panel, so the two larger red wires that attach to the battery positive are sensitive to 'clean' and 'tight'. They often get disturbed during battery maintenance, and more often when a stereo install requires a battery feed for an amplifier. A couple Sharktoberfests ago, one guest had managed to leave them slightly loose while prep'ing the car for a concours event, and had severe overheating problems in traffic through Los Angeles getting to our event. We spent a while diagnosing the usual ways, including swapping those modules you have swapped. I had two prior experiences with cars that had the same symptoms that turned out to be those battery connections, but the car owner assured me that the connections were secure. After a few hour we decided to pull the spare out and look...

So clean the connections with a brass brush or maybe a little sandpaper, to the point where the metal is shiney. Don't polish through the tin coating to the copper if you can help it, hence the brass brush recommendation. Tighten the nut securely on the stud and confirm fan operation. Then apply a coating of Vaseline to the whole connection to prevent any new corrosion. The battery vent tube is often left off of the battery when a new one is installed. If yours is gone, consider replacing it so that fumes are vented out of the battrery well. I used a bit of black plastic drip irrigation tube from the gardening section of the garage to make one, and routed it out through the cable grommet towards the ground (down) at the front of the battery box.

As always, lift the ground strap first when working on the battery. Clean all the connections while you are in there, just because it's easy once the spare is out.


HTH!

draco's keeper

Sab, I had a lot of intermittent gremlins and after cleaning(with ultrafine finishing pads,contact cleaner then a very lite coat of dielectric grease) all grounds and relay terminals most have not returned. If you can jumper the hot wire (usually we don't put a fuse in line of proper amperage/load) and it works thats a telltale sign of bad ground) Dean AAT( I agree with Mike, DR's dual fan set up is the way to go,I have no problem upgrading this car to make it more reliable as long as it can be reversed back to stock without ruining value.I've put this fan set up on the last two trucks I've owned with no problems. Dean

draco's keeper

dr. bob beat me!

DR

Sab,

Take a very close look at the actual connectors on the fan harness where it attaches to the fan. They are simple spade connectors inside the housing and can get loose from plugging and unplugging them. I just noticed the housings on mine were brown and starting to melt from the arcing of the connectors being loose. If they are, take a small screwdriver and push back the release tabs on each female spade connector, pull it out, use some pliers to bend the connector 'tabs" so it fits tighter on the male blades of the fan connector and reinstall.

Sab

Thanks for all the replies,

Mike, that thermo switch sounds good for a last resort if I can't figure out what is causing the problem. I may have to go that route by the weekend.

Bob, I cleaned up the battery connections with 1000 grid sandpaper last night and finished it off with electrical cleaning spray. After bolting it back together, no change . So that was not the cause.

draco's keeper, I will clean ground connectors on the weekend.

DR, I will check on that today, hopefully that's it.

Just barely made it into the office it with the AC off and the heater on to keep engine temps low.
Thanks again,

dr bob

Sab--

Sorry we didn't know about this sooner. I was camped out at a power plant project just south of Lakeland for a few weeks, came home over the weekend. I would have gladly taken a break from work to fix your car with you. Any time spent on a 928 is better than work!

Jerome Craig

This is what I found in finding/repairing my fan gremlins.
Fuse#28 was distorted by heat - although it still tested as "good"; the fuse's plastic had started to melt and was coating the copper connector - causing intermittent contact at first, then finally no cantact; and the heat had distorted the terminal block surround. Since cleaning the contacts and removing the surround, I have not had any problems. I have ordered a replacement surround.

Jerome

Sab

DR is the winner...

finally got to examine the connector today. It looked fine at first, but upon closer inspection the plastic is real brittle and some parts are broken off. One of the connectors has moved and apparently does not line up with the receiving plug.

After many tries I got the fan tu run for now. I will cut the connectors out and rewire.

i am pretty sure this is the culprit.
Thanks a lot. I will post once I complete the rewire.

Jerry 87 928S4

That was the same problem I had and DR was able to get me new connectors.

shadowknight

Jerome what is the part number for the connector, I have the same issue as well and would like to order the part from the dealer.

Sab

Just a final update. At the end it turned out to be not noly the connector on the harnes, but the connector on the motor was bad. So I had to replace the fan motor. All is good now.

UKKid35

Same happened to mine, the connector on the motor had become so hot it desoldered itself. This happened 1,000 miles from home, luckily I had a soldering iron with me and manged to remove the fan shroud early the following morning in the motel car park in order to fix it.

MattCarp

I'm overhauling my cooling system on my US 84 S.

The car is being worked on and doesn't have a battery installed.

I'ld like to disconnect the fan at the connector, but I can't seem to separate the connectors with my hands. Are there locking tabs on the connector, or, have my metal spades corroded together?

Thanks, Matt