AC comp not engaging

[55CrownVic]

I replaced compressor and rec/drier and had system charged about 2 months ago. Everything working great. Then started the hot out of one side and cold out of other. Replaced the DCCV -not easy with 75 year old arthritic hands. Filled and bled system. Now AC comp will not engage clutch and fan doesn't ramp up when select AC. Fuse is good, relay ohms out good. Should still have a good charge since ac was working before I changed DCCV. Question is should fan ramp up to high speed when ac button is pressed even if comp doesn't come on? Any ideas appreciated.
Ben
Edit: DATC self test returned 12 42 recirc door fault. No other faults.

 

[1LoudLS]

Question is should fan ramp up to high speed when ac button is pressed even if comp doesn't come on? Any ideas appreciated.

I would think that it wouldn't in at least some circumstances, such as one of the problems where the car knows something is wrong and is not turning the system on for a reason.

 

[joegr]

The engine fan won't speed up unless the AC high side pressure goes up. If the clutch isn't engaging, then the fan's not going to speed up. First things first, what the pressure in the AC system.

 

[55CrownVic]

Don't have gauges to read pressure right now. Will get readings Monday and report them.

 

[1LoudLS]

just an FYI...

the low side port is hidden behind a piece of plastic behind the drivers wheel, can be accessed with out pulling the wheel off if you have a lift, it still can be accessed on the ground with the wheel on, but its a pain in the ass...

 

[cammerfe]

You might try 'jumping' the power wire to the compressor clutch. Some years ago I was working on a Pontiac. I found hidden in the wire loom a fuse holder. The fuse holder was shot and had an 'open'. A straight wire might tell you something.

KS

 

[joegr]

It might also quickly ruin the system...

 

[cammerfe]

I wasn't suggesting driving it on a daily basis. But, with the engine running, a momentary touch of power will tell you that the clutch---and compressor--- are at least functional in some degree.

If direct power makes things go I'd then start looking at the factory wires. If tracing back doesn't, then, uncover some sort of 'open', you'll have to look further.

The magnetic clutch actually makes a bit of noise when it pulls in so I suppose you'd not even have to have the engine running to get some sort of indication. Good luck!

KS

 

[55CrownVic]

Got a set of guages and checked the system. No pressure at all on high or low sides. Apparently the shop didn't find the leak when I had the ac serviced. Will take it back and get it looked at again.
And I agree with you, Loud, low port is in a lousy place. Thanks for all the replies everyone.

 

[55CrownVic]

Follow up question. When running the DATC self-test on 01 V8, it runs the test and gives an error. Then instructions say to press auto to exit and clear codes and unit will boot to an off condition. Mine boots to: Auto, AC, and shows 75 for each side. Would this call the results of the self test into question or not anything to be concerned about. I get this result with engine on or off. Thanks.