2nd Gen Non-Engine/Transmission Heater woes

[Bpostel]

Hey guys looking for some help. The heater in the truck is ain't working to good. Not thermostat, it comes up to temp fine around 190. The little servo blend door is moving fine when I turn the dial for the temperature from hot to cold. Here's what it is doing. When I turn it to the feet it puts out decent air. When I put it to the defrost it doesn't blow out very much and it's alot cooler air. Not sure what that would be. I check the hoses going into the heater core and one is around 140 and the other is around 143, the truck wasn't all the way up to temerature when I checked these. Anyone have any ideas?

 

[dseabaugh]

when on defrost the air conditioner runs too so it could be cooler, especially if not warmed up fully.

 

[2-ND TIME]

heater probs

what I have been finding withe mine is one of two things. The fan motor is going? failing, not to hard to do 1/4 wratchet with some long extentions and a u-joint and ????10 mm I think it is. ( and if you are 100 lbs) I am not. Or the temp selecter. It is easy to take out better if the inside cab temp is warm. Over the years I have been finding that one of the copper buss bars inside is turning blue. They arent' worth tring to fixxing for the short time that this extention lasts. The back of the unit comes off this will show if the bus bars are turning colour. I have been getting mine from a junkyard place.

 

[Bpostel]

I thought the defrost runs of the air condition, but the air is really cool coming from the defrost. If I turn the mode selector to just defrost it's warmer, but when I put it to defrost and floor heat the defrost doesn't blow much air and it's pretty cool and the floor heat is warm. I'm about ready to tare the dash out and start replacing everything in order to get some heat.

 

[2-ND TIME]

It sounds as if the air conditioner isn't working ( low freon) you should get the same temp air coming out of both vents for what was selected. What is it one should have max AC, defrost, defrost/ floor is it? think there is one more? The rest are just temp controlled air coming in.

Sorry I didn't read it very carfully. Does the air conditioner make cold air then as the dial is increased , will it increase the air temp to some form of hot? If not this could be low freon. Then next step would be to determine does the selector work for the different positions. This then would be a vacuum / selector problem.

 

[Bpostel]

The air condioner is works really well in summer. Yesterday I drained the antifreeze and back flushed the heater core. A few pieces of rust or dirt came out but not much. The water seemed to flow through pretty good no obstructions. I decided to change the radiator hoses while I was at it, I had to order them so I'll get it back together today and see if anything changes.

 

[DShore]

There are only 2 positions on the heater/ac control that the a/c compressor does not run. One is on the floor only position, the second being the one coming directly out of the dash. A/c operates to some degree in all other positions except off. At least that's the way it works on a 1998... hope this helps.

 

[Bpostel]

got everything back together and it has helped some. I picked up about 20deg. of warm air coming out of the vents according to the temp gun. So it did help, probably won't run you out of the cab but better. Maybe sometime go ahead and change out the heater core. Thanks for the help.

 

[Mike Ellis]

I am about to change the heater core in my '97, starting to smell antifreeze in the cab when I turn on the heater :{.



Went to the auto parts store and the heater core they had looked it was soldered together by a chimp. Went to Dodge to get the "real" one and it is nearly $250 :{ :{ :{



When I get the old one out I wonder if it is possible to get it fixed to keep for a spare?