Cooling fans only work for a couple of seconds

[Kenny_Z]

Yesterday I noticed my temps climbing to just above the first mark whenever I'm at a stop light. I wanted to make sure my fans come on so when I got home while the car was still hot and running I jumped out to look. They were not on. Today I went out to jump the otterstat and driver side (I think) comes on for just a couple of seconds and then cuts off. I've looked through threads here but I haven't found anything that sounds like my issue. There's an unmarked fan system in the car, I do not believe it is a fanzilla. I'll have to go take pictures of it during my next break.

I was hoping to take her to a show tomorrow seeing as I have missed every other one this summer but if I can't figure this out I'm not risking it. Any ideas?

[Chris4099]

Normally I would suspect your circuit breaker. If it's going bad, it could be tripping after just a few seconds of use and cutting power to the fan. However most fan modules bypass it. But until we see some pictures, we won't be able to say for sure.

[Kenny_Z]

Sorry about the delay. It's been a hectic day. Here are the photos. Sorry about the glare. Yeah, I see fuse 7's case is cracked. I'll have to fix that tonight. Thankfully I have spares.

http://uploads.m-cgi.com/kennyz/Delorean/Projects/misc037.jpg
http://uploads.m-cgi.com/kennyz/Delorean/Projects/misc038.jpg

I thought I took a photo of under that black box but I guess my phone ate it. It's just two connectors, dual pronged.

[Bitsyncmaster]

Since your one fan is working for a few seconds my bet is that fan controler is bad.

You can use a standard relay (one of your headlight or blower relays) and make the fan fail jumper to go to the show.

[Chris4099]

Looks like the main power that is driving the fans is coming from the circuit breaker. But you could have a problem with the fans and/or the controller box too. Dave's recommendation is a good one. Just get rid of the box and restore the wiring with a standard relay and a fan jumper on the blue socket. Also verify the fan circuit breaker still has both wires attached to it (in case the PO disconnected one).

Then when you retest, you can confirm if both fans work. If it still stops after a few seconds, that also confirms the circuit breaker is bad.

[DeLorean03]

Knew a guy up here with a near identical sounding issue. Turned out his otterstat was bad. He jumped the otterstat as well, and because they were stock fans, the circuit breaker was tripping, causing the fans to only come on for a couple seconds.

[Kenny_Z]

Dave was correct, that controller is bad. I was able to bypass with the jumper and an extra relay I had and all is well. That explains the dead battery I had two days ago. That box must have fried itself.

Looks like I'll be putting in an order for one of Dave's fan fail boxes soon.

[Kenny_Z]

Everything is running great but I had no idea how much fans could pull on the idle voltage. Good thing I have a good alternator installed. I definitely won't be driving at night until after the upgrade.