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Discussion Starter #1
So I started noticing my mazda's ac was occasionally coming on and off and the problem seems to be getting worse now, or I'm just noticing it more in the summer. The problem would occur under various driving conditions, stop and go, highway, etc. Usually the AC would blow cold for 10-15 minutes, then warm for 5-10, then back to cold, but these intervals are not always consistent and sometimes it turns on and off at varying intervals. The problem seems to get worse as the ambient air temp is higher. I've replaced the AC relay, checked refrigerant levels, and verified the clutch is engaging when I turn the ac on, and I can spin it freely when the motor is off. When I first bought the car a few months ago I noticed the led on the AC button would occasionally come on and off on its own and that seemed to coincide with the ac not working but now the led stays green even when it's blowing warm air.

My plan is to check the resistance on the compressor clutch coil next, and possibly bypass the thermal protector and see if that makes a difference.

My concern is while I'm doing my testing I may not be catching the offending part in the act since its not easy to pull over on the highway and pull out a multimeter as soon as the problem comes up and since I'm crawling under the car I won't know if the AC starts working again.

It may just be me being overcritical looking for the culprit but my radiator fan does seem to be louder than usual. I'm doubtful its the problem I think doing 80 on the interstate would still be enough to provide airflow to the condenser but that's just me guessing. If anyone could let me know if this is accurate or not that'd be great. I haven't seen any big increases in engine temp while this is occurring.

Besides the coil and the thermal protector what else should I check next?
 

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So someone on another forum suggested it could be a fan speed switch and after a little more research this seems to be a common problem on these cars. Any tips for testing this further? Can this effect the AC engagement without any problems with fan speed, as my fan always blows at the right speed it just sometimes is warm and sometimes is cold?
 
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