[jtm78]

Hi all, this is my first post since I just signed up today. I have some questions I hope someone can help with. Earlier this summer my ac started shutting off while driving if the outside/ ambient temp got over 93 degrees. Then it would do it when when it was 85 degrees. Finally I noticed that it was mostly at lower speeds around town with lots of starting and stopping...... So, I changed the fan clutch, that worked for a week or two while the ambient temps were down, then it started getting hot again and it seems like it takes 5 minutes or so to start to blow cold air. And it still cycles off and on. I drove about 30 miles on the highway without stopping and the air would blow cold then hot then cold ect ect...... Also now the fan started screwing up. Sometimes it will blow harder on the passenger side, sometimes it would not adjust from high to low, then the weirdest thing, I turned of the truck and the fan kept running!!! Thanks to this site I think it's the blower control module, fingers crossed. Also at one point I changed the low pressure switch. Any help is appreciated!!!:thx

 

[jtm78]

Cool, 45 views and no replies.... :worried:

 

[burninator]

No idea. I was just chasing my own A/C problems and found that this crap is beyond me to diagnose. Once you check the basics it's better for me to leave A/C issues to the professionals.

I know that doesn't help you, but I can sympathize.

 

[c good]

you have an excessive "air gap" and/or a weak compressor clutch field coil. Very common on this vintage. Remove the shim under the clutch plate or get a new field coil. Field coils are impossible to find so you may have to get a salvage yard compressor and take the field coil off of it. Otherwise you'll need to get a a new compressor and open the system. Than requires evacuation and recharge. Pull the shim out first. Then go from there. HTh c goood

 

[jtm78]

you have an excessive "air gap" and/or a weak compressor clutch field coil. Very common on this vintage. Remove the shim under the clutch plate or get a new field coil. Field coils are impossible to find so you may have to get a salvage yard compressor and take the field coil off of it. Otherwise you'll need to get a a new compressor and open the system. Than requires evacuation and recharge. Pull the shim out first. Then go from there. HTh c goood

Thanks, what does pulling the shim out do?

 

[c good]

Removing the shim reduces the "air gap". It basically brings the clutch plate closer to the magnetic field coil, giving it a better chance to grab the plate and engage the compressor. If this doesn't solve the problem then you've got a very weak field coil. Pull the shim first then get back to us for the next step if it doesn't solve the problem. HTH c good

 

[jtm78]

Removing the shim reduces the "air gap". It basically brings the clutch plate closer to the magnetic field coil, giving it a better chance to grab the plate and engage the compressor. If this doesn't solve the problem then you've got a very weak field coil. Pull the shim first then get back to us for the next step if it doesn't solve the problem. HTH c good

Okie dokie, thanks!