Last week the heater and heater blower worked just like it should with all variable speeds. Parked the truck when I got home one night with blower workingand the next morning no blower at all. Hot air comes out of the vents but not able to use blower. Winter is coming here in Maine and I am going to need to fix this problem or freeze my _ _ _ off. The truck is a 1990 Dakota SE Extended Cab 3.9 Autowith A/C. Any idea what the problem could be? Someone said maybe the relay is bad but I can't even find where it is in my Haynes book. Fuse is good.
All help appreciated before winter really hits......

 

check your fuse block under the dash there may just be a blown fuse

 

The fuse is good. Any other suggestions? Was told that there is a heater/ac relay somewhere on the firewall. Any idea where on the firewall? Inside or under the hood?
Thanks for the response

 

You probably have a bad resistor block. Here's what I did on my 89: http://gbrannon.bizhat.com/resistorbox.htm
Regards,
Greg

 

If that all checks out alright, check for power and ground at the blower itself.

 

There is no blower motor relay in these trucks. There is a relay for the A/C compressor, but in no way is that related to your problem.
Like gb6491 said, its probably your resistor block, which is a common problem. The link he provided will show you where the resistor is located at (in the even that link doesn't work, there is a picture in the FAQ's post at the top of the Gen 1 section which has a picture)., and how to remove it.

 

once again the Dodge Forum comes to my rescue!!! heater is up and working again , best of all it didnt cost any $$.

Thx
Ken

 

How did you you fix it? I have replaced the resistor with a brand new one and the fuse in the fuse box is good and yet no blower motor... and it is cold!!! I get heat blowing out the vents while driving just no blower motor. I have been trying to figure this out since I got the truck and it still doesn't work. I do not have power at the blower motor, but I do have ground.



Later Daze,
Shorty

 

The ground for the blower motor is provided via the resistor block (so, the ground flow is from the blower motor, thru the resistor block, to the actual speed selector switch on the heater/ac control unit, to the ground).
There must be an open between the fuseand the blower motor(provided power is getting to the fuse). Power goes directly from the fuse to the blower motor (it does not travel thru any other connectors).

 

thank you!! I will go look further at it tonight



Later Daze,
Shorty