1990 240sx. Air Conditioner Light power source. Where is it?

[RamonetB]

Hey guys,

I've been going through the FSM trying to find where the power comes from to turn on the Green light when your press the AC button in. After getting my AC going again (Was the Thermo Amplifier: in another thread, thanks for the help guys!) I've noticed the issue with the light hasn't disappeared.

It sometimes goes on and sometimes goes off. Never indicative of whether or not the AC is actually on. After an hour of driving, it reacts as it should. This tells me there's another loose solder joint somewhere.

Does anyone know where the power for the bulb comes from? is it the ECCS control unit?

Thanks.

-kirk

P.S. No, it's not the environmental control unit. I've replaced it (for other reasons) and the behavior is the same.

[elwesso]

Its going to be in the actual controller, theres nothing that comes fromthe ECU directly to that bulb.

Does the AC act normally, or does the AC go on and off accordingly when the bulb is on/off?

[RamonetB]

AC acts normally. The light doesn't dictate when the AC is on or off. Although, after 2 hours or so of driving, the light acts normally. Perhaps something in the wiring harness? When I swap the environment control unit into another 240, it works fine. It's something with my car somewhere.

[elwesso]

have you simply tried replacing the bulb?

[RamonetB]

Yes. No change.

[RamonetB]

Figured this one out.

Turns out it was bad solder joints, alright. Or at least worn old ones. But the problem was in the control unit itself. And there were A LOT of bad solder joints in that thing.

It's all working fine now, and the lights brighter than ever. Why it worked in the other 240 is beyond me.

It doesn't matter anymore anyway.