Just got my 'new/old' truckyesterday!, a 1999 green Expedition EB and everything is great except the AC ....

everything appears to be functioning except it blows hot (front and rear), the compressor will cycle on and off every few (5-10?) seconds.

I thought maybe just low refrigerant/slight leak or something and was hoping I could just add a can to fix. Well, I don't know this truck at all, and not even sure where the low pressure side fitting is ...I thought the obvious fitting on the passenger side front (near radiator) would be it, but my gauge(I would always check pressure first) and my hose (both with quick-connect fittings) that I used to use with my old truck (that had R134a refrigerant) doesn't even fit. This fitting (and line) also seemed pretty hot where I would have expected cool.

I'm a total newb with this truck, so take it easy on me, but can someone point me in the right direction?? What's up? I was assuming it used R134 coolant (am I wrong? I know there's different fittings for different coolants). Is the low-side somewhere else?

hard to diagnose the actual problem from a post, but is there any checklist you guys would go thru to determin the problem? I was just assumming low charge or leak due to the cycling compressor. I did do a search, could that blend door issue cause this? any other known issue on Epxy's that could cause this?

Thanks in advance for any advise, and hope I found the right forum for my new ride

 

It sounds like your low on refrigerant(134a). Look towards the firewall on the passenger side. This is where any AC line would come out of the evaporator and that would be low side. The filter/drier is usually located there as well, sometimes the low side port is on that. Generally the low side lines are bigger in diameter than the high side.

 

Sounds like you were trying to connect to the high side condensor line fitting. Do you have both high and low side R-134 connectors or just that low side charging kit? As 94broncoxl said you should find the low side connector around the larger suction evaporator line between the firewall and the compressor, possibly right on the drier. In any case if you don't have both gauges I wouldn't mess with trying to charge the system. I would have the system completely evacuated and vacuumed an then add the specified amount of R-134 listed on the tag next to the evaporator case or on the front radiator cover.

John

 

Plus if you're low on freon it means there is a leak. Check all the A/C hoses and connections for traces of oil. Most likely you've got a bad O-Ring somewhere with a small leak.