The thermal limiter blows instantly when i turn the a/c on. Its a small plastic block with a 3 wire connector on it that clips onto the underside of the compressor bracket . a/c was working , than shut the car and blew the thermal when i went to put it on again. Changed part and it blew again as soon as i turned a/c on. Thanks for any help. John
Thermal limiter is working as a fuse. Current flow = heat. AC compressor drawing too much at start-up is the symptom. Cause could be a bearing issue or a short somewhere downstream in the wiring.
Steve thanks, I'll start checking the wires. its blowing by just turning the key to the on postion putting the fan on.
Actually, it sounds like the superheat switch in the rear of the compressor has failed or the system is lowon refrigerant. The job of the switch is to monitor the compressor temp and short to ground if the temp gets too high. This blows the thermal limiter and stops the clutch from engaging. To monitor the system charge, remove the connector from the back of the compressor, replace or bypass the thermal limiter and connect your gauges. A quick check is to feel the suction pipe at the compressor. It should be cool and sweaty when the AC is running.
Thanks for the info. Im thinking from what you said it could be the switch. a/c wasnt blowing ice cold but was acceptable before the problem started. Is this switch replaceable.
The switch can be replaced, but finding one might be tricky. The refrigerant must be recovered for replacement. The switch is held in by a snap ring. Test the switch with an ohm meter to ground. It should be "open" when the system isn't running. It should be open, too, with the system running and the refrigerant charge at the proper level. It sounds like maybe your system was low on refrigerant or had other pressure related issues. Check with your local NAPA store, they should be able to order the switch. If not, email www.ackits.com to check price and availability.
