BACKGROUND: Car is a 2002 Z28 with about 22K miles on the clock. No problems to speak of up until this past weekend. No changes have been made in the last several thousand miles that would affect this problem.

On Saturday morning (rainy and humid) I had to run an errand in my Camaro. Noticed the Service Engine Soon light was on so I pulled out my Predator and ran a quick scan. Error codes were P0480 and P0481 (Cooling Fan 1 and 2 Control Circuit Malfunction, repsectively). Tracked it down to a blown 40A MAX (read: big-***) fuse. Swapped the ABS fuse for the blown fuse and the SES light went out ... for awhile. Then the fuse blew again. Rather than replace a $2 fuse every half hour, I decided I'd better figure out what's causing the problem.

Anyone experienced this problem before and have a suggestion for where to begin looking? Hate to pay a deler $70/hour to fix something I could do myself. I friggin' HATE electrical systems in general, but if I know where to begin I can probably figure it out. Like Spicoli's dad, I've got an awesome set of tools and I'm not afraid to tear into it if there's a chance of getting it fixed without laying out cash.

Thanks in advance for any advice!

Brent

 

As followup, I went out and pulled the fan to test it out. Hooked it up to 12V power source and each fan spins up just fine. Thought I'd throw that out there....

 

This is a quick cut-n-paste of an email I sent to some buddies begging for help. Hope someone here can help me out now that I've done some more testing!

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Problem is with my '02 Camaro. Over the weekend it tripped the CEL. Quickly tracked it down to a blown fuse on the cooling fan circuit. Swapped the ABS fuse (one of them big ol' 40A "MAX" spade-type fuses) and it blew after a short time -- probably as soon as the fans went to kick on. Before I blew another fuse at $2/ea I decided to tear into it a bit. Here's what I've found:

1. The fans seem to be fine. Hook 'em up to direct 12V and each one spins up as expected without hesitation.

2. Using a continuity tester on each fan wire pair, I get the following:

FAN 1 white = continuity
FAN 1 lt blue = no continuity

FAN 2 white = continuity
FAN 2 black = continuity

Testing was done with ignition off, red multimeter lead on the wire being tested and black lead on a good ground, and a new fuse installed but never powered up. I cannot test it with current going through the circuit (AFAIK) because I'd have to get the engine up to temp in order to get the computer to kick the fans on, but I can't do that with everything torn apart as I currently have it. (But having said that, I think it would blow the fuse as soon as current started flowing anyway.)

I'm **FAR** from an electrical expert, but I shouldn't have continuity on BOTH wires going to the second fan, should I? My task now is to trace the wire back and figure out where it's grounding out, right?

Hope someone can either confirm my uninformed theory or straighten me out so I can get this car back on the road. Can't take Noelle's Durango from her too many days in a row, especially when I need to leave for work Thursday before she even gets off of night shift. :-(

Thanks a ton,
Brent

 

With the fan relays out, I get continuity at the fuse box for Fan 2 white wire but not Fan 1 lt blue wire (as described above). Does this have any significance for my troubleshooting process? I'm having a b*tch of a time trying to get at any of the wiring because of the @!#%$ ABS stuff in the way.

I also have continuity with one probe on each fire for the Fan 2 circuit. That just doesn't seem right.

 

Quick thought -- if I simply pulled the relay out for Fan 2 and got by with Fan 1 alone for a couple days, am I still going to blow the fuse because of the [apparent] short in the wire?

 

have you messed with the relays at all ? possibly in wrong.. the two wires going to the fan are the only two ? if so trace the wirse back up and look for one to be missing its coating.. i dont have the wiring in front of me so i cant exaclty help too much. i dont know off hand wich color does what.

 

I didn't touch the relays prior to the problem occurring, no. After the problem showed up I swapped relays around to make sure that I didn't have a bad relay, but I'm quite certain they're all in properly. If there's a spot open, this baby's going to the car doctor tomorrow for expert attention. I've narrowed the problem down as much as possible but I'm turning it over to guys with a lift and time on their hands to actually fix it. I've done about as much as I can with my current facilities and time; now I just need it fixed so I can drive it.

 

start at the end of the circuit and disconnect connectors until you have no more continuity to ground. then you will have isolated your short.

 

Problem is that the wire disappears into the frame and I can't (in a short timeframe) access it properly to diagnose further. For better or for worse, I dropped it off at the dealer 15 minutes ago and should have the problem resolved by the end of the day. I couldn't have made it much easier for them to fix -- told them what the symptoms were, where the problem was, and left the cooling fans out so they could get at the stuff easier. Only thing more I can do is sign the check at the end of the day.

 

Just got the car back from the dealer. Bad wires as I suspected. Had to pay for an hour of labor, but it beats trying to do it myself when I need the car for daily transport. Thanks to everyone who offered suggestions!

 

Just a quick update: following my last post, the fuse blew again. Took it back and this time they told me it was really a bad fan motor (even though the first work order clearly stated that the fans were tested and were good). Paid another $70 for the "diagnosis" and went home to swap fans. A couple days later I turned on the AC again and yet another fuse blew. Took it back to the dealer for a third time; they spent the entire afternoon tracking down the problem, which supposedly was a stray screw poking through the wiring harness from the fenderwell area. We discussed it and ended up splitting the labor cost. I didn't want to argue -- I just wanted it fixed permanently, which thankfully it now seems to be ... $300+ later, anyway.

Just wanted to throw that out there in case anyone else ever comes up against a similar problem....

 

glad u got it taken care of,,my P0480 comes and goes when it pleases, all relays replaced,,,,SES stays on most of the time, but goes off every now and then,,,,my dealer is 80 an hour,,sux