help troubleshooting a/c compressor not engaging

[gsmcsw]

i have a 89 bronco with a 351 in it and i'm trying to find some troubleshooting info for the a/c. i tried the tech manual but it doesnt have any info. i tried searching this sight and couldnt find anything...

the problem i'm haveing is that no matter what position the temp selector switch is in, the a/c compressor wont engage. i checked the fuse(#9) and it is good. i cant find a wireing diagram to help with takeing voltage or resistance measurements. can someone please direct me in the right direction? another question i have is does the a/c compressor engage when selector is in the defrost position on this truck?

thanks

 

[Broncobill78]

i have a 89 bronco with a 351 in it and i'm trying to find some troubleshooting info for the a/c. i tried the tech manual but it doesnt have any info. i tried searching this sight and couldnt find anything...
the problem i'm haveing is that no matter what position the temp selector switch is in, the a/c compressor wont engage. i checked the fuse(#9) and it is good. i cant find a wireing diagram to help with takeing voltage or resistance measurements. can someone please direct me in the right direction? another question i have is does the a/c compressor engage when selector is in the defrost position on this truck?

thanks

Gosh, I wish I had more to offer you. As far as the defrost thing goes yes it engages the AC when you select defrost. I have to admit I never really used it very often & the only thing that comes to mind is a problem with the clutch not engaging but AC just isn't my gig.

 

[2NDTOUR89]

My thought on the ac thing is that first have it checked for pressure. If you have a full system of freon, check the cycle switch at the accumulator. You can bypass the switch with a jumper wire to see if you can make the clutch engage. If it does cycle, and you have a full system, check your orifice tube (also at the accumulator) in the line to see if it has a blockage. You will need to have someone evac and recharge it for you though.... Hope this might help...

 

[Rocky]

i have a 89 bronco with a 351 in it and i'm trying to find some troubleshooting info for the a/c. i tried the tech manual but it doesnt have any info. i tried searching this sight and couldnt find anything...
the problem i'm haveing is that no matter what position the temp selector switch is in, the a/c compressor wont engage. i checked the fuse(#9) and it is good. i cant find a wireing diagram to help with takeing voltage or resistance measurements. can someone please direct me in the right direction? another question i have is does the a/c compressor engage when selector is in the defrost position on this truck?

thanks

Are you turning you "fan" switch on? Mine won't send the a/c clutch a signal without turning on the fan.

Rocky

 

[2NDTOUR89]

I think that all of the trucks with slide switches (up to 91) all have fan power once the mode switch is activated (meaning when you slide the switch to activate any mode, vent, defrost etc. the fan turns on low. The only way to turn off the fan is by sliding the mode switch to the off position. The later ones 92-95 you have to turn fan switch to power up the fan and ac clutch.

 

[gsmcsw]

I think that all of the trucks with slide switches (up to 91) all have fan power once the mode switch is activated (meaning when you slide the switch to activate any mode, vent, defrost etc. the fan turns on low. The only way to turn off the fan is by sliding the mode switch to the off position. The later ones 92-95 you have to turn fan switch to power up the fan and ac clutch.

thanks for the help. i did try turning the fan switch up and down and still nothing. i will have to try to jumper the pressure switch this weekend if its not raining. (seattle area) is the pressure switch the one on the accumulator? it sure looks like a pressure switch.

 

[Roadkill]

That would be it. Here is a picture of one on my '96. It's partialy obscured by the heater hose, but you can still see it.

 

[skinsgamer]

I've had some a/c issues in the past. Even changed the a/c clutch. My experience with the clutch not engaging at all is the system coolant is low or empty. When was the last time you had it serviced? I used to live in Oak Harbor, Wa and we'd go a couple of years without needing a/c, so I would run it once in awhile just to keep the system lubed.