whahappened

Greetings All,

2004 Acura TSX (non-nav, 5AT). First, I have been using the existing A/C threads to troubleshoot my issue which has helped me narrow down the problem, so many thanks for that! So here's the deal:

PROBLEM: A/C does not come on at any setting with the A/C button on or off. By not come on, I mean the compressor does not engage.

- A/C fuse (#30) in the dash box is fine.

- A/C compressor clutch relay is tested and fine.

- Jumper'd the A/C compressor clutch socket (pins 1 and 2) and the clutch engages the compressor fine. This bypasses the A/C low/hi pressure switch. The A/C blows cold air with the clutch jumpered and the lines coming out of the evaporator get very hot/very cold, so the system has a good charge.

- At this point, I removed the jumper and reinstalled the clutch relay. I then removed the A/C low/hi pressure switch connector and jumpered the connector pins....no A/C. Hmmm. When I connect a multimeter to one of the connector pins and body ground, I get something around 0.02-0.06 volts.

My assumption has been that when you press the A/C button on the climate control system, the car computer checks the A/C low/hi pressure switch condition, checks any additional interlocks, then sends control voltage (pins 3 and 4) to the A/C compressor clutch to engage the compressor (pins 1 and 2). So somewhere in that electrical system something is getting lost.

So now I am stumped and have a few questions.

1) Is my assumption above correct or are there other components/fuses/relays I can check?

2) Can someone check their A/C low/hi pressure switch connector by disconnecting it, hooking up a multimeter to the one of the connector pins (please check both) and body ground (or negative battery terminal), and letting me know what voltage they see when the climate control button is turned on and off?

3) Any ideas would be greatly appreciated!

-- whahappened

TexasHonda

You don't test the pressure switch by measuring voltage across it or from one of the legs to ground. You measure the switch resistance w/ ohms measurement function of VOM. Switch should show a dead short all the time.

However, since AC did not come on when you jumpered the AC pressure switch connector, the pressure switch is not the problem. You can measure resistance to confirm the switch is closed (shorted).

There is a thermal protection switch that is in series w/ the AC pressure switch. If it is open, it would be same as an open pressure switch and would disable the compressor clutch. The thermal protection switch is on the compressor body. There are two wires to the thermal protection switch; blu/red and red. You could again jumper the connector to see if that enables the AC compressor to engage.

Problem could be caused by defective thermal protection switch or possibly overheating compressor.

If you don't have a shop manual, I would suggest purchasing one. check automanualsource on ebay or direct.

good luck

whahappened

A huge thanks to TexasHonda!

Checked for continuity between pins 1 and 3 on the connector coming from the thermal protector...nada.

Found the thermal protector connector and checked for voltage, which was about 10 volts, which is good. Jumped the two pins and the compressor kicked right on. Need to replace the thermal protector.

For those who encounter the same problem, the part number is:

38908-RBB-A01 (~$50).

The replacement instructions can be found here (pages 151-153):

http://www..com/forums/content/manua...l%20System.pdf

Thanks again!

HEAVY_RL

iTrader: (1)

I really appreciate you coming back to share the solution.