I have been having problem with my Trane unit from 1995 from last two month. I am been calling the repair tech last two time for the same problem! And this is third time same problem again I think.
1. Tech said the transformer blew up so he replaced the transformer
2. Tech said transformer blew up again he replaces the transformer and found the short where its blowing up the transformer. He also places a 5volt fuse in case it the short blows up the transformer again! He told me replace the fuse if the ac won't work
3. Again today the ac stop working. I went to ATIC upstair the fuse didn't blow up but still replace the fuse and press the manual black button and the unit turn ON but it won't turn on automatically through thermostat. So I though may be the thermostat is bad had the same before when I call the tech twice. I took the thermostat upstair and replaced it works great and did vice versa. So thermostat is not the problem.

Is the transformer blow up again but than it won't work by pressing the black button. Is it
White roger obsolete ignition modules??

Again dreading a $100 bill coming soon :(

I would check low voltage control wires from air handler to compressor unit, especially if exposed.
I prefer to pull control with power wiring, providing the right insulation. Keeps wiring protected.Tech may look in air handler for pinched wires.
Maybe a contactor/relay with shorted windings, drawing excessive current. Amprobe will tell.

I would check low voltage control wires from air handler to compressor unit, especially if exposed.
I prefer to pull control with power wiring, providing the right insulation. Keeps wiring protected.Tech may look in air handler for pinched wires.
Maybe a contactor/relay with shorted windings, drawing excessive current. Amprobe will tell.

Thanks for answerig the question don't have amproble will get it from work tomorrow!
But can you tell me what wiring I should look for really confuse what it looks like! Still newbie to all the stuff! Since just bought a house

There are some pinch wires but what do you mean control wires and insulation wire.

Many people run a pair of low voltage wires from air handler to compressor unit, when thermostat is set to cool, 24 volts goes on that pair of wires to the compressor contactor, if you don't see a 2 or more wire cable, then High voltage wiring is likely run with supply wires in the conduit.
Thermostat to air handler is other low voltage wiring.

Many people run a pair of low voltage wires from air handler to compressor unit, when thermostat is set to cool, 24 volts goes on that pair of wires to the compressor contactor, if you don't see a 2 or more wire cable, then High voltage wiring is likely run with supply wires in the conduit.
Thermostat to air handler is other low voltage wiring.

Hi
Thanks for your help. I resolve the issue. It was something related to thermostat. The tech did it for free since it was 5 min work.
Thanks again