A month or so ago, the air conditioning in our '99 Grand Caravan (3.3) started blowing warm while we were driving. Shortly thereafter, I noticed that the temp was rising rapidly. As we were just blocks away, I was able to make it home. After taking a look at it, I discovered that the radiator fans weren't starting. I did the google thing and found that it was likely the fan relay. I replaced the relay and all was well - until Monday.

After a short trip to drop my youngest daughter off at school, I noticed that the temp gauge was climbing very fast. I made it home just as the needle pegged the H - no telling how hot it actually was. What I found when I popped the hood was that the radiator had cracked right at the upper tranny line. Pulling back into the driveway, I noticed that the small puddle I had seen earlier was not from the sprinkler line that had been spraying the driveway but was, in fact, antifreeze. As my daughter is the everyday driver of the van, there's no telling when the radiator may have actually cracked. What I do know is that there was very little, if any, coolant left in the system. I replaced the radiator, checked for fan & A/C function and, once again, everything is fine - until today.

Once again, I noticed that the A/C started blowing warm and checked the temp gauge right away. Sure enough it was climbing. I shut the A/C off and the temp leveled off slightly above normal. Luckily, I made every light on the few miles home and it never got any hotter. As before, the radiator fans are not running. Out of curiosity, I attached a recharge can to the A/C's low side (yes, I realize the gauges on the can aren't always accurate or dependable but I figured it would at least give me an idea). Sure enough, the low side is running at about 130 psi.

Here's my question:

The first time I replaced the fan relay, it seems that I read somewhere that the A/C system has been known to, in some way, cause the fan relay failure on Caravans. I can't find that article or post or thread for the life of me now. So...

Is the A/C issue in some way causing my fan relays to toast or am I dealing with two separate issues that coincidently seem to occur simultaneously?

Any insight to either problems (A/C psi &/or fan relay) would be greatly appreciated.

 

Either the fans themselves could be drawing too much power or the relay itself could be bad. I like to put thermal grease between the relay and the frame to keep the relay cool.

 

Just change my rad fan relay, then my rad fan fuse was blowing, my rad fan themselves were bad and yes my ac was blowing warm. Now after replacing fans and relay, no overheating and ac is cold. I have a 2000 GC 3.3.

 

Thanks guys! I'm curious about the relationship between the relay frying and the A/C blowing warm. Is there a correlation somewhere or is it just coincidence that it's happened twice now?

 

the a/c doesn't work if the fan doesn't work. the high side pressure gets too high and keeps the compressor from engaging.

 

Tizzy: Yes, the a/c will not work if fans are not operational at all.

Question: How about, if the fan or fans are working intermittently or if the the radiator is not getting hot because air is blowing across it, say at 70 miles an hour. Would the a/c still not function if air is blowing across the radiator. I thought it was a temperature thing and not--the fans not working. Please let me know.

 

Yes, lots of highway driving and the a/c will probably work. It is a pressure thing, but that also is linear with temperature. If you were doing mostly city driving, it probably won't work very well. Compressor cuts out at 450 - 500 psi and won't reengage until it is below 350 psi. If it were above 90 degrees and humid outside, even driving the a/c might not work.