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Topic: A/C blower kicking off when climbing even slight inclines (Read 181 times) previous topic - next topic
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A/C blower kicking off when climbing even slight inclines
On a recent return trip home my A/C fan on the dash worked fine until I had to use more power to climb slight inclines on the highway, then it would stop blowing cold air.  The air was still cold so it didn't seem to be the A/C itself.  As soon as I leveled off the blower would start again.  I took it in for service and a check valve was found to be not working, so it was replaced.  This was the check valve that is close to cab itself so dog house had to be removed and it was an expensive repair.  Apparently there is more than one check valve.  I was told it was a valve that was supposed to only allow air to pass in one direction, but the defective one was allowing air both ways. 

But it didn't really solve the problem, and now hot air was coming into the cab by my feet when the blower kicked off, so it's back at the service place.  Has anyone else experienced this problem, or have any idea what really is going on.  The rig drives fine otherwise.  It's a 2000 with about 76000 miles.  It gets serviced at normal intervals but isn't used as frequently these days so it's longer periods between service - oil changes, brakes etc.
2000 TK
Re: A/C blower kicking off when climbing even slight inclines
Reply #1 –
This is a common problem and the cheap fix can be found at:
Article 82 on
Yahoo! Groups

Bob
2000 MB
Re: A/C blower kicking off when climbing even slight inclines
Reply #2 –
Thanks Bob, I checked the article and that led me to more articles that I had missed about the same subject and the related loss of air flow when applying gas on a hill.  Apparently it is not at all uncommon but had only just begun to be a problem in my rig.  It looks like replacing the check valve was a reasonable move since mine had failed.  If the vacuum line is still a problem that will be next move.  But it reassures me that my repair place is not selling me a story.  They may have missed replacing the insulation in the duct work for vents under the dash in a hurry to get the rig back to me before a planned trip.  They have it back now and should fix it!  Fortunately, while expensive, it wasn't as bad as the dealer charges I've seen quoted!
2000 TK