78 Heater electrical issues

[fireaxxe]

Hello fellow CJ5 'ers, I recently purchased a 1978 CJ5 Renegade that has had at least two previous ovners who have done various "upgrades". It came from Texas so one of the PO's had disabled some of the heating system. I live in Colorado so I would like it working. I can unbolt and bolt things but electrical isn't my forte. Here is my delemma:

I did the Blazer motor upgrade which seemed to go well. When I hook the motor directly up to the battery it spins. When I hook up the power wire that goes through the firewall I get nothing. If I check that power wire with my multimeter i get 12v. Why doesn't it spin with the power wire?

Impress me with your knowlege....

 

[Lumpy Grits]

WELCOME
Did you have IGN switch 'on' or in the accessory position?
LG

 

[fireaxxe]

Digg, I've tried both. Starting at the fuse block I now have no power across the "heater" fuse with my volt meter. I know this thing is nearly 40 years old (I'm 51) but I'm getting frustrated chasing wires!

 

[Torxhead]

Then I would suggest getting a wiring diagram so that you can use color coding to help you out. A Haynes CJ manual has them, but it will take you awhile to figure it out. Good Luck!

 

[Lumpy Grits]

That bigger blower pulls far more amps than the OEM did. You may well have to 'up' the wire gauge and fuse amperage.
LG

 

[IOPort51]

If you are reading voltage "across " the fuse it indicates that the fuse is blown.

 

[Peanut Butter]

Always start with a good wiring diagram. Here's a link to one you can buy: Prospero's Garage I bought one and think they are great. Also check for the coiled resister inside the heater box. Might have gotten thrown away, as many people don't know what they are for.

 

[caveman]

Make sure that the motor is grounded well. Some times just bolting it in isn't enough.