A/c compressor only kicks on with bypassing main fuse in fuse box..

Cichyb · Post by **Cichyb** » 05 Aug 2016, 06:49

1998 s70 here quit blowing ac. Found 10 amp fuse blown and replaced, AND also the icecube (relay/fuse) -- black one
still nothing.

Bypassed the pressostat plugin (or low pressure) still nothing. have 12v going to plugin..

replaced the pressure switch down there by the light
still nothing

bypass the icecube relay in the fuse box and voila! I check pressure at about 45.psi

any ideas? ---maybe the pressostat? ecm?

thanks

Post by **abscate** » 05 Aug 2016, 07:30

It sounds like the AC clutch is pulling too much current. That probably means its at end of life. You can replace the clutch without replacing the AC compressor or breaking lines.

AC pressure measurements don't mean too much in diagnose unless you carefully control the conditions - If your AC was working well before, go for the clutch replacement - used is fine.

Set the gap first!!

Cichyb · Post by **Cichyb** » 05 Aug 2016, 07:46

would shimming it help?

Post by **abscate** » 05 Aug 2016, 07:54

Probably not. If its pulling too much current, there is an electrical fault. You could try measuring it by going to a 15 amp fuse as a temporary measure, or if you have a good ammeter, measuring the resistance of the clutch connections while they are disconnected from the car. The need to be greater than 2 Ohms or so to stop that fuse from blowing.

You are risking burning up your car bypassing the fuse or using the oversize one - Legal Department.

Cichyb · Post by **Cichyb** » 05 Aug 2016, 14:53

burning up car in terms of what? catching fire LOL or screwing the a/c system up?

Post by **scot850** » 05 Aug 2016, 14:59

The former!

Neil.

Post by **BEJinFbk** » 05 Aug 2016, 19:58

Of course, catching the car on fire won't do the A/C any favors...

cichy1012 · Post by **cichy1012** » 09 Aug 2016, 18:40

clutch replaced, still nothing. Anything else?

Post by **abscate** » 09 Aug 2016, 19:43

That means a wiring fault between the clutch and AC relay is pulling the current.

Download the wiring disgram from the inter webs and use that as a guide for finding the fault.

Double check the resistance on the new clutch to confirm its a good part

cichy1012 · Post by **cichy1012** » 10 Aug 2016, 12:09

one more questions. as far as fuses and relays that pertain to this.-- the only fuses and relays for this are in the hood correct by the fire wall? nothing in the glove box or on the side? I know im 1994 940 a solder spot broke off in the panel on the board where the knobs were that needed to be fixed and that got my 94 up but i assuming this is different in the 98's