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View Full Version : GMS8 blows fuses when on A/C


ramond
May 2, 2009, 02:34 PM
I've got a Goodman GMS8 A/C and furnace and the problem started a few days ago where:

- the thermostat has no temp reading
- no response when the thermostat is cycled from off to cool or warm (with either set to auto or on)
- no response when I reset power on the circuit breaker
- checked on the LED status light and it's off inside the unit
- checked the controller board and the fuse was blown
- replaced the 3A fuse and it blew again
- replaced the fuse again and I had the thermostat set to OFF (temp) and ON (fan) before I powered it on from the door switch
- the blower comes to life then I asked my helper to switch it from OFF to COOL and it blew the fuse
- checked for any loose or possible short on wires, nothing too apparent. I plan to double check it again today

Any other ideas on what I can do?

Thanks in advance.

Joshdta
May 2, 2009, 03:57 PM
Your contactor outside in the ac is probably bad. Take the t-stat wires loose from the outdoor unit then try it again see if the fuse blowes

T-Top
May 2, 2009, 09:04 PM
Check for low voltage shorts on the thermostat wire from the thermostat to the furnace and to the A/C and check for shorts on the low voltage side at the A/C(low and high pressure switch, time delays).

ramond
May 4, 2009, 02:16 PM
Your contactor outside in the ac is probally bad. Take the t-stat wires loose from the outdoor unit then try it again see if the fuse blowes

Thanks for the response. I just want to understand this. If I remove the t-stat wires from the outside unit and the fuse does not blow, it's the contactor that's the issue. If the fuse blows while the t-stat wires are disconnected, then it would be a short on the t-stat line? Right?

Joshdta
May 4, 2009, 03:43 PM
Correct, odds are the contactor is your problem, inless you hit the t-stat wire while weed eating. Contactors run about $25 and are easy to replace.

mygirlsdad77
May 4, 2009, 03:46 PM
Please let us know what you find.

ramond
May 12, 2009, 05:32 PM
Correct, odds are the contactor is your problem, inless you hit the t-stat wire while weed eating. Contactors run about $25 and are easy to replace.

After so many rainy days, I finally got out and checked the t-stat lines. The fuse doesn't blow when they're not connected. So I ordered a replacement contactor and replaced it today. I've got A/C back!! Thanks for all the help.

:D:D:D:D

Joshdta
May 12, 2009, 06:09 PM
Great, glad you got it going!! Job well done.