Heater issues

Ok so recently my heater just stopped working. I went outside to warm the truck up and turned the heater on. All worked well. When I came back outside I noticed there was no heat coming anymore and I couldn't hear the motor. The switch was on and evergthing. I checked the blower motor and hooked it up to 12v and it spins. I check power at the fuse with a test light and it was fully lit. There is no power at the switch or to the fan. I also replaced the switch with a used switch to try it and still nothing. so where can I check next to fix this problem?? Thanks!

Might be the resistor? Check out Cusser's write up that has some great info on it.



There are also a couple different types of resistors that these trucks came with, there is some info on mazdatrucking forum.



good luck!

Cool ill search and see what I can find.

Jonny - Here's what I understand about your situation: the blower fan spins when 12 volt positive and ground are connected directly to it, so the fan itself is good. You stated "I check power at the fuse with a test light and it was fully lit. There is no power at the switch or to the fan."

So here's my take: you are not getting positive voltage at the fan connector, correct? Then rule out the blower resistor and blower motor switch, because they are on the "ground side" of the circuit. I see on my diagram a circuit from the ignition switch (my diagram shows a BR - black/red - wire) going to a 30-amp circuit breaker and going to the blue wire at the blower fan itself. So if you're not getting any positive voltage to that blower fan, looks pretty straightforward. The grounding circuit from the fan is more complicated, goes through the blower resistor and the fan speed control, but you say no positive voltage to the fan, so start there. So my guess is the ignition switch electrical circuit or the circuit breaker, as I understand your situation...just because your truck starts and runs does not mean that the circuit of the ignition switch of interest here is making contact...

If you PM me with your E-mail address, I'll E-mail a copy of the AC/heater wiring diagram.

Ok so correct me if I'm Wrong. The break switch is that bigger fuse that's one the fuse panel
In th truck correct? And how do u test it?

A circuit breaker is not a fuse; when a circuit breaker overloads and gets hot, it breaks the circuit. Once it cools down, it can do its function again. Typically a re-set is needed, but certain types reset themselves.

Ok so the circuit break was not popped or so I think. The lil red tab in the middle was still pushed in. So now idk what else to try

Bad ignition switch?

See the earlier posts. So there WAS positive voltage coming out of the circuit breaker?

Follow the positive voltage through the wiring circuit, find out what "blocks" it.