I have AC problems with my 98 Blazer 4.3 4x4. The clutch does not engage on the compressor and I'm pretty sure its out of freon. When I bought it, the ac was sluggish until they gave it a shot of freon. Then I assume it leaked out and now doesn't work. Will being low on freon stop the clutch form engaging the ac compressor?

Also, If I were to install a toggle switch in cab, direct wired from the battery with an inline fuse. Would I be able to turn the dial to ac, and flip the toggle switch? Does the compressor normally turn on and off while continuous ac use? If I were to straight wire it with a switch, would i have to worry about leaving it on while the ac was on?

One more thing, with a direct wired switch, what size inline fuse would I need, I'm guessing 30 amp?

Thanks in advance!

 

Yes, low R134a (Aka "freon") will cause the compressor to not engage. If it's already been recharged once, you probably have a slow leak and should be diagnosed. And yes, it is normal for the compressor to start and stop when the A/C is operating normally. I wouldn't suggest trying to direct wire your compressor, it's not engaging right now for a reason, probably low R134a and running it with low refrigerant will cause damage.

 

You would be much better off to actually fix the system than try to rig it up. It will be cheaper in the long run.

I would start off by installing a jumper wire in the low pressure switch connection to see if that allows the compressor to start. If it does, you know you have a low refrigerant level.

 

Ok great yeah, putting in a jumper wire would also prove that the rest of the system functions properly, (control unit in cab, etc). Where is the low pressure switch and how do I install a jumper wire?

 

The search feature does work (some tips)...

The low pressure switch is located in the accumulator/filter/dryer assembly (big silver can) on the passenger side of the motor. It'll have a two wire plug on it.

 

Yep, you were right, I just guessed that that was the low pressure switch yesterday and stuck a bent piece of fence wire in. The clutch immediately engaged on the compressor. YOU DA MAN. When I go to recharge it, do i have to worry about using a recharge that has oil in it? If so, are there any guidelines on amounts, types, etc?

PS. I tried using the search and wasn't aware of the guidelines. I'll use those rules next time, thanks!

 

If, with the low pressure switch bypassed:

• air blew cold - you may have a bad low pressure switch. Get a new low pressure switch and install away. It just threads in and little to no refrigerant will be lost in the replacement (there is a check valve in there).
• cool, but not cold - you likely have a slightly low charge. Get a recharge kit from your favorite parts store (Wal-Mart has them as well) and follow the directions.
• no real change in outlet temp - you may have a rather bad leak that may want to be looked into by a professional.

 

I have a problem with my AC in my 98 LT. It blows hot air out no matter what setting it is on, one mechanic told me something about one of door switches being stuck or something like that. He wanted to much money just to check out rather or not he needed to get behind the dash. Any help is greatly appreciated.