a/c wont shut off

Hi All,

Just joined, nice site. Got a couple of questions.

My a/c compressor runs all the time with the climate knob in a/c settings or heat settings or vent setting. It only shuts of in the off knob setting. What should I check for repair?

Also I bought one of those 143a fill guages. It snapped right on the fitting of my Chrysler sebring but doesnt want to snap onto the windstar hose fitting. It only goes on so far, and I don't want to force it on unless I'm suppose to. Is there an adapter I need to get? Or should I press with alot of force?

Pretty sure I'm on the low side, its the fitting on the hose. The other fitting seems to be built into the receiver/dryer tank. This is the high side ,isnt it?

Thanks,Jeff

Hi Jeff,

The high side fitting is bigger than the low. On the '96 the low IS on the receiver/drier and the high on the end of an alluminum tube extension.

Regarding the compressor running, I would think about the climate knob being a problem - always sending an A/C on command, or failed A/C cycling switch - the cylindrical switch (small one) on the side if the receiver drier. It can be unscrewed and changed without evacuating the system.

Let us know what you find.

Hi Busboy,

Thanks, I assumed the low side was that easy to access tube, never assume! I'll check my pressure, possibly tomorrow, wont be home till late tonite.

Any way to verify if it is that switch on the dryer? How to test to ensure its bad since auto places dont return electrical stuff?

Its not a rush right now, as I use a/c just about everyday,but when it comes time to need heat, I'd rather fix it right instead of disconnecting compressor for the fall/winter.

Thanks, Jeff

Hi
I would hate to have you buy something then not need it, but the more I think about it, the more I lean toward that switch. Reason being: if you disconnect the electrical plug from the cycling switch and short it, the compressor clutch will engage (all other things being normal). In other words, you can demand, with the knob, A/C but if the conditions are not right to close the A/C cycling switch, the system will not run. Since you have the opposite problem I think the switch is always sending power to the compressor clutch.

Hopefully others will jump in here with opinions.

Good luck. At least your system "failed" on the good side :)

Hi,

Yes, I agree, it seems very logical circuit is being made all the time. I'll look at switch and check if I buy one if I can return it.

You got that right!, better to have a/c all the time than not at all!

Thanks, Jeff

The "clutch cycling switch" CANNOT be the problem. Why? Because it should ONLY have power to it when the function switch is in: Def, A/C, or Vent, NEVER in "heat". The test is simple, with a volt meter or test light grounded to the battery, check BOTH terminals of the sycling pressure switch for voltage with the function switch in the HEAT position, if you have voltage, the function switch is bad.

The cycling pressure switch ONLY cycles the compressor based on system pressure, nothing else.

Hi Modmech,

Yes, that makes sense. Appreciate your diagnosis and most importantly your instructions on proper testing procedure. Might get a chance to test tonite if the rain lets up.

Thanks and Best Rgds,

Jeff

Thanks Mod for jumping in and clearing that up.

No problem folks.

Think of the Function switch like a fircuit breaker in your house. If it's on, the lights (and A/C) should work right? If it's off, nothing you do to the light switch (cycling pressure switch) should get the lights to come on.

Have you tried the relay? I am trying to solve the same problem, but only on the rear heat/a/c, and I'm pretty sure it's the relay. Just can't find the darn thing. I know the front relay is in the fuse box, but the rear isn't.

Hi All,

Just joined, nice site. Got a couple of questions.

My a/c compressor runs all the time with the climate knob in a/c settings or heat settings or vent setting. It only shuts of in the off knob setting. What should I check for repair?

Also I bought one of those 143a fill guages. It snapped right on the fitting of my Chrysler sebring but doesnt want to snap onto the windstar hose fitting. It only goes on so far, and I don't want to force it on unless I'm suppose to. Is there an adapter I need to get? Or should I press with alot of force?

Pretty sure I'm on the low side, its the fitting on the hose. The other fitting seems to be built into the receiver/dryer tank. This is the high side ,isnt it?

Thanks,Jeff