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Old 07-14-2011, 05:08 AM   #2
MT-2500
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Re: A/C quits working when it gets 90+

Quote:
Originally Posted by pprince72 View Post
. .....I have a 1998 K1500 and 244,000 miles on the whole A/C system and only had freon added by the dealer about 10 years ago. The problem is the A/C works good up the upper 80's but when the temps get into the 90's and humid the compressor quits working (when I need it most) after 15+ minutes then I turn it back on maybe 15 minutes and up to 30 minutes it works good again then off and so on. The only thing I can think of is a faulty high pressure sensor?
....... My next question if I replace the high pressure switch should I replace the Receiver Dryer or just Evacuate & Recharge the system? I appreciate any thoughts its going to be in the upper 90's for the next week + and thats in Minnesota. Thinking of snow
What makes you think high pressure switch is bad?
Have you checked low and high side readings?
You have to have proper pressure for the pressure switches to work right.
On the 98 I have found the low pressure switches and wiring plug-in to give the most problems.
Any lights flashing or on on control panel.
After a battery change some of them have to be reset.
Is your higth switch mounted on back of compressure on yours?
Or mouted on high pressure line?
If 2 wire line on pressure line it can be checked with a jumper wire.
Or if a single wire switch in compressor it can be checked by seeing it is grounding or switching with high pressure.
If on back of compresser the system has to be pumped down to replace and then vacumed out and recharged with proper charge.

If it has been 10years since charge.
First thing is to check for proper AC charge.

What are your low and high side pressure readings at idle and at 2 K rpm?
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