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Lots of possibilities, one cheap thing to try- Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Thu, 23 Jun 2005 05:43:54 In Reply to: AC cutting out after 20 minutes or so consistently....., NittanySaaber, Wed, 22 Jun 2005 18:43:57 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Low freon levels, bad pressure switches, or even the freeze-up switch may be at fault. But there is a cheap thing to try.
Pull the A/C relay. Pop the cover off. Clean up the relay contacts with a little fine sandpaper. You aren't trying to abrade off the plating - just clean off the black crud. Shine up the contact lugs on the bottom of the relay, and plug/unplug it a few times to polish up the socket contacts. See if that fixes the problem.
The A/C clutch pulls a lot of current, and every time the clutch disengages, it creates a little spark at the relay contacts. This causes pitting and carbon buildup, which adds resistance to the circuit. As current flows through that resistance, it heats up, which increases the resistance. The longer the A/C runs, the more that resistance builds up, until it is too high to allow enough current through to pull in the A/C clutch. Once it cools down, the A/C will work again. But you've got to turn the A/C off to let it cool down - the relay will still close, and current will still flow, heating up the contacts; it's just not enough current to pull in the clutch.
I've had this happen on a few Saabs. The nice thing about this fix is that it is cheap and easy. I like cheap and easy.
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