Air Conditioning blowing fuse 34

jerryg2112

jerryg2112

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Looking for some help with my A/C. I have a 1999 and it keeps blowing fuse #34 which is 15 amps. It takes about five to ten minutes of driving with the a/c on for it to blow. The fuse does not blow without the air. With the car running in park the motor bogs for a second when the clutch disengages. Is this normal or is the clutch hanging up and maybe drawing too many amps? So far I have changed the fuse a half a dozen times. I've cleaned the cycle switch connection and swapped the relay with neighboring relays. I have cleaned the connector on the compressor. I have cleaned the ground by the battery on the inner fender wall. I have not checked any of the reverse lamps or grounds since that part of the circuit is not active when the fuse blows. There is 14 volts at the relay terminals 1 and 3 with the car running. There is also 14 volts at the compressor connector and the cycle switch. I have a couple of tests for short to ground that are in the repair manual that I am going to do. Any other suggestions would be appreciated.
 
All signs point to the compressor itself, or its clutch anyway. That's the only other item on the circuit that's related since you've already replaced the cycling switch. That switch does report to the PCM that the compressor is engaged but I don't see that being able to blow the fuse.

The AC clutch is the only thing left with enough draw to blow a 15a fuse.
 
I didn't replace the cycling switch, only cleaned it and checked the voltage. I did some tests for grounded circuits and didn't find any. It does look like the clutch is the problem. Is there a way to test it and can it be replaced without removing the compressor. I know there's not much chance of that since there isn't any room but it don't hurt to ask.
 
I thought I would try to verify the clutch as the problem before I replaced it or the compressor. I checked the ohm resistance of the coil. It was 3.6 ohms. I also did the voltage tests described in Four Seasons doc: 4S 336 CLUTCH COIL DIAG and all the tests were good. So I'm not sure that the clutch is the problem. The other thing that makes me question the clutch besides the test results is I can run the air in park and the fuse doesn't blow. If the coil was bad wouldn't it blow the fuse all the time? If I'm driving and I turn the air on the fuse blows within a few minutes. Any reason the clutch would pull more amperage while driving? If not then something else in the circuit is pulling too much current. Will keep looking. Next I am going to try to measure the amperage that the coil is pulling in different conditions. I only have a cheap meter. I see if I can get it to work.
 
There is ONE other item on that fuse and you're not going to believe what it is --- the console shifter illumination!

That might be getting pinched somewhere and shorting things when you're not in park. Connector C210 in the shop electrical manual (inside the center console, near left side of glove box) can be unplugged to do a quick test. The circuit also powers the electric PRNDL indicator (orange and white wire) that goes to the dash display. All of this assumes a center-console shift car and not the 6 passenger option.
 
I did some circuit to ground tests that I mentioned in my first post. One of the tests had me unplug connector C210. After the test I left it disconnected to see if the fuse would blow with it unplugged which it did. It's still unplugged now. I have the 6 passenger model.
 
Then I think the "blows only when in gear" part is a red herring. In gear = lower rpms = lower voltage = higher amp draw, which might be just enough to put an almost failing part over the edge.

You've reached the end of the theory and now it's time to drop coin till it's fixed. It will most likely be the compressor that solves the problem - it's never a cheap part.
 
Just posting a follow up. While I believe the problem is the clutch, it's gonna have to wait a while as a few hundred dollars is not in the budget right now for a new compressor, dryer, and freon capture and refill.
One thing that has been bugging me is that I could not find G101. Even though I don't think that the connection is poor because there are a lot of other things grounded to it and they are fine, I am irritated that I cannot find it. Does anyone know where it is exactly?
 
Well it's almost a year later and I've finally replaced the compressor. I was going to take it to a shop and have the reclaim, recharge done while I changed out the compressor myself. Then my wifes Pacifica ac seized up. I wound up buying a Robinair RRR machine off craigslist and did the reclaim myself. My ac is fixed and blowing cold air. Hopefully the fuse problem is gone now. Time will tell. Her car is next.
 
Still blowing the fuse. I pulled the fuse and connected my multimeter in its place so I could monitor the amperage while driving. There's less than 1 amp till I put the car in reverse or turn on the AC. Each one of those pulls about 4 amps. I did some driving with the air on and the amps stayed around 4. Then while I was driving I pushed the car which pushed the rpm up to 3000 before it shifted. The amperage suddenly jumped up and blew the fuse on the meter. Shortly after that I replaced the fuse and revved the engine in park up to 3000. No change in amperage while in park at higher rpm. Why is the amperage draw jumping up under load? Any ideas anyone?
 
Hey thanks for this post. I've been having the same problem in my 99 for years. Tried chasing it down for a while but eventually just gave up and have been living without AC. Murder in the summer.
I thought I'd checked all the grounds; and am not finding any grounds in the service manual particularly near the Trans dipstick. Are you referring to the one on the firewall near the ECM? That's the closest one im aware of.
 
Problem wasn't a ground. It was a grounded wire. The harness and wire insulation wore away and the wires were making contact with a tube that looks like the dipstick. I found it with a led light. Key on, jumper the relay. Compressor unplugged and a bulb in its' place. Move all of the wires around that you can and watch the bulb for a flicker or light off.
 
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