Heater motor not working

[usraptor]

When I rebuilt my heater box, '70 'Cuda, a few years back, I bench tested my blower motor and it worked fine.  Fast forward a few years, heater box and motor are installed in car along with dash and gauges, switches.  Now when I turn on the ignition, and turn the fan switch on the dash on, the motor does not work.  Doesn't matter which speed I put it on.  I checked the wiring to the back of the switch and I have power at the black wire going to the switch.  The other two wires are dead.  I re-attached the connection to the back of the switch and checked the wiring at the heater box.  The dark green, (two prong connection) shows power when the fan switch is on.  There is no power to the light green wire.  There is also no power on the single connection.  Electrical is definitely not my forte, but as I see it I'm getting power to the motor.  Not sure what the other two wires do.

So do you think my switch is bad on the dash or the motor?  Also, is there a way to jump the motor via the connections on top of the heater box and if so which two connections do I jump?   

[Cuda Cody]

Yes, you should be able to add 12 volts (just a short burst) and see if the motor works.

You can test the switch with a multi-meter.  Use the ohm setting.

[1 Wild R/T]

Yes, you should be able to add 12 volts (just a short burst) and see if the motor works.

You can test the switch with a multi-meter.  Use the ohm setting.

"In a short burst"  Sorry, Mopar blowers barely blow because they don't get enough power.... First off I'm betting your blower resistor is bad, it's the part with all the wires attached behind the glove box.... Second even in the high speed mode Mopar adds resistance, I bypass the resistor & add a high speed relay.. Suddenly you get some decent air movement out of your blower motor....

Anyway, try jumping power from the dark green wire to the single connection... Going off memory the single wire feeds the motor.... So no you don't have power to the motor...

[70/6chall]

How about the fuse?   Thanks,   Al

[usraptor]

Thanks everybody.  Fuse is good.  First thing I checked.  I'll try Wild R/T suggestion and check the resistor and jump the wires.

[usraptor]

Damn I hate being stupid!  While trying to jump the connections on my heater box, as recommended above, I  noticed that the ground wire wasn't connected.     I connected a jumper wire to it (with great difficulty because of the small space and where it was) and then grounded the jumper wire to the frame.  Reconnected all the wires, turned on the ignition and turned the blower fan on and guess what?!  It fired right up.  Now I just have to figure out how to permanently ground the wire as it's virtually impossible to get to without dropping the heater box assembly which I really don't want to do right now.  Like I said, I hate being stupid!      The only consolation is that I won't be driving the car in the winter and it doesn't have A/C, so I really don't need the blower motor to work.  It's just the principal of the thing and my stupidity that pisses me off!    

[Cuda Cody]

Glad to hear it's working when you got a ground to it.  It's nice to have defrost when you need it.    

[1 Wild R/T]

Go to fridge... Grab beer... Crack open Beer... Sit down... Relax.... Drink beer..... Repeat.....Tomorrow is another day.... Don't you feel better now?

[Rev-It-Up]

Damn I hate being stupid!  While trying to jump the connections on my heater box, as recommended above, I  noticed that the ground wire wasn't connected.     I connected a jumper wire to it (with great difficulty because of the small space and where it was) and then grounded the jumper wire to the frame.  Reconnected all the wires, turned on the ignition and turned the blower fan on and guess what?!  It fired right up.  Now I just have to figure out how to permanently ground the wire as it's virtually impossible to get to without dropping the heater box assembly which I really don't want to do right now.  Like I said, I hate being stupid!      The only consolation is that I won't be driving the car in the winter and it doesn't have A/C, so I really don't need the blower motor to work.  It's just the principal of the thing and my stupidity that pisses me off!    

Don't feel bad!  You would die laughing if you knew half the stuff that happens in our garage.  We go by the Vegas motto..."What happens in the Pixie Garage, stays in the Pixie Garage"!

[usraptor]

Yeah, I often wonder why I undertook this much of a project and question if I have the skills and patience necessary to undertake a full restoration. Especially like this morning when I discover that I made a stupid bonehead mistake.  Then when I fire the engine or sit back and admire the car and compare it now to where it was when I bought it and began this adventure, I'm glad I did.  Even though if it hadn't been for the helpful and encouraging people on CC.com and here at E-bodies I would have never gotten this far.