Hey guys, I have just recently replaced the radiator in my 95 Prelude SI (old one had a crack along the top). Anyway I put everything back together today and go to run things over and everything in the car works except for the AC. When I put the AC on, the defrost light blinks off and on for some reason. Weird because the AC worked fine before...

Only other thing I did besides replace the radiator was swap out the old Honda headunit with a Kenwood MP3 player. I soldered all the wire connectors and heat shrinked them.

Anyone have any ideas why the AC wouldn't work and the defrost light blinks on and off whenever the AC button is pushed in. If it helps, my engine also seems to be making a winding noise whenever the AC is turned on, (sort of like the car is surging). When you turn the AC off, the engine idles fine.

 

I don't know much about the AC in hondas cause I dont have it anymore with my swap, but I can try to help, and bump for some more help. The idle surging is normal, when ur stopped and u turn the ac on it puts more of a load on the car so it surges a little. When u put the new radiator in did u remember to put the AC condensor fan on too? Also when u put in a new head unit make sure u didn't cut the ac signal wire, does the AC light still come on when u push the button? Since this just happened after u replaced the radiator and head unit I would check everything u worked on to make sure there's nothing u missed.

 

Yeah I installed both fans and verified that both were working, the A/C light does come on however when you turn it on, the defrost light turns on and blinks as well. I have never seen/heard anything like this before.

When I installed the new head unit, I bought the wiring harness adapter from audio express, and soldered all the wires with the unit outside of the car, so I did no cutting at all. Just simply solder and plug and play. I did however, blow a fuse in the car when I first installed the cd player (two of the solders became exposed and I guess they collided with each other and caused a fuse to blow). It was a 10A fuse and I think it was the ACC one, but I have already replaced it because without it the headunit would not work.

 

see if pounding on the dash near the top right of the control unit makes the ac work... if it does then i can help u fix the problem

 

OK I messed around with the car a lil while I was on lunch break, the car only seems to surge at idle whenever the rear defroster is turned on and you have the A/C on. When you turn the rear defroster off, it keeps blinking even though it is turned off. Apparently it only keeps blinking whenever you have the A/C running, if you turn the A/C off and or run the heat and turn the defroster off, it stays off and does not blink.

So obviously something whack is happening to the defroster which is causing the A/C to malfunction...any ideas???

And no, banging on the dash didn't change anything with the A/C.