No Heat

[84GNTTYPE]

Last week I replaced the heater core on my '84 GN. Since then I have had no heat.

First we thought the system was maybe airlocked. So we took off the radiator cap and let the car warm up and idle for quite ahwhile. This should work the air out of the system, right?

I still had no heat, so we took the hoses off of the core and ran water throught the core to make sure that it was flowing. We got plenty of water out the other end, so there isn't anything blocking flow.

The vacuum line to my heater water valve is broke, but with no vacuum the valve is open.

I have the eletronic touch climate control. When I was looking under the passenger side dash, I noticed that there was a plug that was not plugged in, so I plugged it in. If you open the glove box, it plugs straight up into a socket on the left side of the glove compartment. I think it has 5 wires, with a space between the last two. It doesn't really seem to make a difference if this is plugged in or not, but I thought it might help with the analysis!?!

A little bit of irony, before my old core broke, it heated great and all the time. No matter where I adjusted the temperature to I always had hot air coming throught the floor vents. It seemed the faster I went the faster the hot air would come in through the floor, and eventually a little bit would come in through the defrost vents too.

Thanks for taking the time to read this, hopefully you can help me out because my dad(a diesel mechanic) and myself are really at a loss.

 

[84GNTTYPE]

No one?

Come on, someone out there must know something about these heaters.

If you don't know about them could you tell me who does so that I can contact them!!!

 

[ChrisCairns]

Re: No one?

Originally posted by 84GNTTYPE
Come on, someone out there must know something about these heaters.

If you don't know about them could you tell me who does so that I can contact them!!!

Hell, just run some of that hot air into the cab.

Sorry....lol.

Does hot water go through the core? Feel both hoses and see if they're both hot.

If they're hot then I would think the flapper valve that allows air to go through the core is closed. You should be able to move that flapper by hand....it's under the dash behind the glove box somewhere around that plug-in.

And that's the end of my heater knowledge.

Chris

 

[Silver 6]

The water valve in line under the hood controls the flow of hot water.

Under the dash there is an arm on the back of the heater box. It hides behind the glove box like that plug you found. The arm is on a shaft going inside the heater box to control a dampner door or flap. This controls the blending of the hot and cold air to give the temperature you select inside the car.

In a manual control system you just need to follow the cable to find the arm. I am not sure about the electronic ones. The arm breaking is a common failure point and it is available from most parts places as well as GM.

 

[Tom87GN]

I lost my heat for a while when I first bought my GN. It doesn't have the electronic climate control like yours, but maybe this will work.

When I was searching around behind the glove box looking for my answer, I reached around behind the control station and just made sure (by touch) that all the connectors were secure. I did this with the car running (important). After messing with them for a bit, all of a sudden, HERE COMES THE HEAT. Ever since then my heat has worked fine.

I know it's not scientific or anything, but it worked. Maybe you've already tried this, but if not, give it a whirl! You never know.

 

[84GNTTYPE]

It seems like the pipe going into the core is hot, but the one coming out is still warm, but not scalding hot like the other.

Thanks for the help, I'll check into it soon!