Heater won't work

[fordeater]

Ok, so i got a new blazer on sunday. I dropped a motor in it tuesday and wednesday, got it running good, and now i'm working on the little bugs. One problem is that the heater/blower won't work. I don't know what it is. I checked fuses, all of them seemed ok. I don't know which relay goes to the blower motor, so i can't check that. Anybody have any suggestions? Kinda hard to defrost the windows with no heat.

Thanks
Doug

 

[cbbr]

If you tested it before you put it in I wuld check the ground wire. If not, test it (hook it ddirectly to the batt) and if no blow - they are about $15-$20 IIRC at Autozone.

 

[Storm Trooper]

Do you have a meter? Check the voltage at the blower. Poor connections will heat up and cause a failure. If you have voltage there, check of contenuity through the motor (complete curcuit). You can pick up a cheap meter almost anywhere.

 

[darkshadow]

well it the moter still works (3 foot chunk of wire will find out real fast)

then check the resistors, the heater box on the fire wall has a pulg in it. 3 wires go to it and one goes to the moter, remover the two screws and pull it out.
(i would recomend spraying something on it first, tends to rust in to the plug)

if the little coils are rusted and busted then replace it.


if its fine then pull your dash and bezel and pull the heater controls and make sure the wire is pluged in to the fan switch.

if it is cut the wire a bit and check for voltage with the key to "ON"

if it dosent have any you have a cut wire or bad fuse ( please check ALL fuses first or you will be pissed. all of them)

 

[fordeater]

yeah, i suppose i should check all fuses. The other day i was trying to fix the radio in the work truck, memory wouldn't work, so i check basic fuses. None were blown. So, about a week later i realized there was no horn, changed out the HORN fuse and the radio worked.

 

[fordeater]

ok, i got it blowing now, and the heat works, BUT, i can't change from vent to defrost or anything else. It just stays on vent. I have no clue what this would be. I thought maybe the switch on the a/c control panel, swapped those out, still same thing. Any ideas?

Doug

 

[fatbob]

My '77 k20 had cables, but some of the new ones have those vacuum operated doors. You just said you got a new blazer but you didnt say how new, or a/c nona/c. need more info. Also, I remember readind a post about the little clips attached the vent doors, breaking off, and not opening or closing the doors anymore.

 

[pvfjr]

My 78 had vacuum, and broken clips.

 

[fordeater]

Its an 84 k5 Silverado with a/c. I'm assuming its vacuum, but do i have to take apart everything to check that the doors are opening and closing?