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Glenn
Dodge Dakota
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6/13/2007
00:02:19
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 Subject: no A/C at idle
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Message:
On my 2000 4.7L the A/C doesn't put out cold air at idle, but does just fine at road and freeway speeds. The engine has also been running really hot when at idle with A/C turned on. If I let my truck idle for 30 minutes with the A/C on, I'm positive it would overheat.
Also, in the months leading up to this problem, my compressor would often make a pretty loud whirring noise. The noise is now gone.
I just checked the low pressure line, and it's at 40-60psi with the compressor engaged, and goes way higher (into the red) when the compressor clicks off. A bottle of refridgerant wouldn't even go in. Also, the smaller diameter A/C line is super hot to the touch, while the low-pressure line feels nice and cool.
The truck has 130k miles on it, and is used about 15 times each year in the Mojave desert, where the silt gets into everything.
Any ideas as to what could be causing this? Please, save me a $1000 trip to the dealer! :)
Glenn@West.Net
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daddio
Dodge Dakota
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6/13/2007
08:27:49
| RE: no A/C at idle
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Message:
it sounds to me like the aux electric cooling fan is not coming on for some reason. that's where i'd start. that aux fan should run on demand for a/c and engine temp above 130 deg F or when engine temp gets to 210 deg f.
could be the relay, fan motor itself, temp switch, etc....
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GraphiteDak
GenIII
6/13/2007
12:16:55
| RE: no A/C at idle
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Message:
Exactly what daddio said.
Driving at a descent speed down the road will move air across the condenser and radiator without the fan so that's why it works.
I just got back from looking at the wife's Grand Caravan. The stupid thing went into the "H" for the second time. On Monday she didn't call me until she got off of the stop and go traffic and onto the freeway where it dropped back to normal. The only reason her BLOND mind noticed anything was the extra red light in the gauge that came on!
It did it again today just as she was almost to the freeway and I had her pull over and turn it off at the closest gas station. Of course it was cool when I got there :p
The only problem I found was maybe a possible bad connection which once I got the fans on, the problem would not re occure while I was looking at it. And worse yet, on that thing it doesn't use relays to turn on the fans like our Daks use. It looks to have a variable speed controller with a large heat sink on the end of the power cluster for the electronics. Now I get to take that apart later and clean/tighten the harness pins and hope that was it!
Anyway. If it runs hot in stop and go but cools at speed it's usually a bad electric fan or slipping fan clutch on a belt driven fan.
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partsmanager
Dodge Dakota
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6/14/2007
09:50:21
| RE: no A/C at idle
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Message:
Graphite get a new relay!!!! ASAP those things were SH!T from day one and have been updated many times. what year is your caravan look at the label on the relay and see if its blue thats a newer one they even had a recall on those relays How old is your caravan? if you have time send me your VIN and ill run it for you
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Glenn
Dodge Dakota
JOIN HERE
6/20/2007
00:29:40
| RE: no A/C at idle
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Message:
I think you guys may be right about the cause of my lack of A/C at idle.
I ran the battery directly into the electric radiator fan, trying both polarities, and nada. Not even a tiny noise at all. When I spin the elctric fan by hand, it turns freely, but squeeks a little.
The 30A fuse for the fan is still intact, and I wasn't sure how to test the relay.
So do the electric fans on V-8 dakotas run directly on 12v? Do you think I should buy a new fan? If so, any tips on a cheap one?
Thanks a bunch!
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daddio
Dodge Dakota
JOIN HERE
6/20/2007
10:12:39
| RE: no A/C at idle
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the efans run on 12vdc. if you put 12vdc direct to the fan from the battery and it didn't turn, i'd say it's toast. i have seen some go out without blowing the fuse or relay.
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Glenn
Dodge Dakota
JOIN HERE
6/22/2007
14:33:28
| RE: no A/C at idle
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Message:
Gents,
I put in a new electric radiator fan, and that fixed it!
Thanks a bucnh, guys!
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