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93 voyager


mac200's Avatar
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06-26-03, 05:40 PM   #1  
93 voyager

I have a 93 Plymouth Voyager( V6,3.0L). When I turn on the defogger fan the A/C compressor comes on without pushing the a/c button on. What would cause this & how can I fix it? Thanks for any help.

 
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06-26-03, 05:55 PM   #2  
It is just normal in a lot of cars. It clears the windshield much quicker this way.

 
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06-26-03, 06:22 PM   #3  
Joe_F
Nothing to fix. It is normal, supposed to be like that and correct.

Air conditioners dehumidify as well as cool. That's what you want when you want to defrost .

 
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06-27-03, 04:32 PM   #4  
I bought the car new in 92 and this just started happening last fall. Not just the defogger but whenever I turn the fan on.
Thanks for the leads.

 
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06-27-03, 04:48 PM   #5  
I would get the wiring diagram and the multimeter out. I would start with the switch and move to the wiring that goes to the relays that turn on the fan and A/C to see if something wore through. GOOD LUCK!!!

 
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06-27-03, 06:41 PM   #6  
on your car the compressor will come on everytime the defroster is used regardless of a/c button selection, however if it comes on for heat,floor or face without the a/c button selected, that could be a problem(if it really bothers you) the heat will always overpower the cool air so you won't be without heat in the winter if that was a concern. if you're so motivated, i'd take out the heater/ac control head(it won't come out far) and see if there is a plug for the a/c button only, (i think there is) and unplug it and see if the compressor stays off, i've seen a LOT of different cars with sticky buttons from coffee and soda getting splashed into them, it could be stuck 'on' inside but showing 'off' on the outside

let us know

 
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06-28-03, 10:33 AM   #7  
Sorry , I had my facts all wrong. The compressor clicks and comes on for 1 second shuts off for a few seconds clicks and comes on for a second then shuts off over & over until I turn it off. This only happens when the a/c switch or the defogger switch is on.

Thanks

 
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06-28-03, 12:29 PM   #8  
the most likely cause for that---low freon, caused by---a leak. the compresser comes on, lowers the pressure on the 'low' side to a point under the low pressure cut-off switch, with the compresser off the pressure builds back up to trip the switch back on to allow the comp to come back on, etc. etc. eventually enough will leak out so it doesn't come on at all. what any good shop needs to do is charge the system with freon and dye, let you drive the car until this problem happens again, then they can find the leak(s) with an ultraviolet light

ps. i've done a lot of evaporators on these years vans(under dash) hopefully it can just be an o-ring or H-valve

 
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06-28-03, 07:55 PM   #9  
Thanks I'll try charging it. I have to drive it to the beach and back this thursday & I'll see how it works out. It's a 10 yr old & not worth a big a/c bill.

 
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06-29-03, 12:46 AM   #10  
Joe_F
If it's low on refrigerant, you must find the leak before charging it. It will be for naught if you don't.

 
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06-29-03, 04:41 AM   #11  
Quick
Originally posted by mac200
<< The compressor clicks and comes on for 1 second shuts off for a few seconds clicks and comes on for a second then shuts off over & over until I turn it off. This only happens when the a/c switch or the defogger switch is on. >>

The compressor is designed to run when both of the conditions mentioned occur. If the compressor is cycling when the defroster is on (regardless of the temperature selected or the temperature outside), this is normal. The system is designed to work in this manner. If it is occurring when you have the temp controls set to cool and the unit is not cooling properly, the symptoms indicate improper line pressure.

There are high and low pressure cut off switches that are designed to shut off the compressor unit when the pressure in the lines reach certain points. Low pressure can indicate a lack of freon or air in the system while high pressure can indicate blockage somewhere. If you don't have a set of a/c gauges to determine line pressure, try the following.

First, turn on the a/c and set it to max cooling with the blower on full. Does the compressor kick on and continue to run for long periods? If it does, and the system is cooling, you're fine. If it comes on for a while and then starts clicking on and off as you've described, this indicates a high-pressure problem (blockage) and the system will require service. If it does not run a while and just clicks on and off as soon as you turn the a/c on, it indicates a low-pressure problem (lack of freon).

There is a small sight-glass built into the a/c line. I believe it's located on the right (passenger) side of the engine compartment, near the fender, on your vehicle. Wipe off the glass (it's almost always covered with dirt or grime) and look to see if there are a lot of bubbles passing through the lines (when the compressor is running.) Bubbles can indicate a low-pressure condition (lack of freon). Since you've indicated that you bought the van new in 92 and this is the first time this has occurred, you may be able to just have the system charged to resolve the problem if you are seeing bubbles.

Hope this helps.

 
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06-29-03, 11:28 AM   #12  
I put in leak stop & 1 can of 134a. This made the compressor stop short cycling. It has a full charge & its blowing cold air. Whether it leaks out, time will tell. You guys are great. Thanks for your help.

 
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