electrical issue - mustang

[Domestic Disturbance]

Put a new heater core in it the other day, and before putting the dash back in I realized the blower motor is now not coming on. Fuse is good, and hvac control is getting power, but nothing else. Also when the hvac controls go from off to on, the backlight for them comes on. This makes me assume there's a bad ground somewhere maybe? Honestly never had to deal with this before so I'm pretty novice.

Things I'm going to try.

- Jump power to blower motor directly
- Check fusable link from ground off radiator core wherever that is

Any other steps, ideas, or advice would be greatly appreciated. I like to get this thing back out by saturday.

[SledgeWS6]

Throw beer at it...that always works with the women folk.

[Sleepy]

Throw beer at it...that always works with the women folk.

Comment matches avatar photo oh so well. Fantastic show.

My guess would be ground also. There has to be grounds under the dash. Any come lose while the heater core was being installed.

Are there any other issues? (typically many things share the same ground)

Do you have a mustang fsm?

[snickerlicker]

Put a new heater core in it the other day, and before putting the dash back in I realized the blower motor is now not coming on. Fuse is good, and hvac control is getting power, but nothing else. Also when the hvac controls go from off to on, the backlight for them comes on. This makes me assume there's a bad ground somewhere maybe? Honestly never had to deal with this before so I'm pretty novice.

Things I'm going to try.


- Jump power to blower motor directly
- Check fusable link from ground off radiator core wherever that is

Any other steps, ideas, or advice would be greatly appreciated. I like to get this thing back out by saturday.

You are on the right track, check for 12v power to the blower motor first, time to get your voltmeter or test light out...If the HVAC is getting power you should be able to check for power out of the control head to the blower motor. And if you swapped an LS engine in it GFY...LOL

[slow ride]

It's only resistant to the LS motor due to the cheap speed offered;) Don't worry it will assimilate.

[Domestic Disturbance]

still haven't gotten this figured out. anyone want to help before saturday?

[fox_stang]

check for power at the plug that goes into the blower motor..also check the resistor which will be right next to it as well..search on google for wiring diagram of the hvac...or maybe as simple as your hvac contols went bad?

[slow ride]

If you have power at the blower plug with the unit on and the blower will run if you jump it from the battery you likely have a bad connection somewhere in between the control board and blower motor. Try using a test light or something with more load on the circuit which will show bad connection. A meter has high internal resistance and will not load the circuit. If you can measure the blower motor when connected to the controler in the on position (assuming the motor is good) this will load the circuit.

As you can tell this is a lot easier for me to think out then type :), but it shouldn't be that bad. Since it worked before I'm sure it's just a missing connection, broken wire, etc. from moving things around.

[Scott]

You say you dont have the dash back in yet?? I dont remember the factory wiring very well but maybe its possible the metal in the dash needs to be grounded to the body to complete a circuit... maybe try jumping the metal dash reinforcement to a good ground and see if it works.

and look really hard for something you forgot to hook up.. I doubt you fried something just changing the heater core unless you broke a connector or something but I would think you would remember that

[Domestic Disturbance]

You say you dont have the dash back in yet?? I dont remember the factory wiring very well but maybe its possible the metal in the dash needs to be grounded to the body to complete a circuit... maybe try jumping the metal dash reinforcement to a good ground and see if it works.

and look really hard for something you forgot to hook up.. I doubt you fried something just changing the heater core unless you broke a connector or something but I would think you would remember that

That had gone through my head. I don't have power at the plug to the blower so I'm going to ground the dash to the car and see if that is the issue.

[BGjohnson]

Just check for ground and power at the plug, if good, your heater core took out your blower motor.