morning guys i had blower motor stop working only turns really slow when plugged in......i replaced resister....still nothing...fuses are good relay is good and i got 14v going to plug...thing is..when i plug blower motor turns real slow sometimes...sometimes not!...when plugged in my dash lights go bat sh&*t crazy....when i unplug it everything is fine...when i hook blower up to battery direct she blows like a french *****....im stumped? can a blower motor work on a battery direct but still be bad?

 

Manual or auto HVAC ? What year of truck you working on ? What brand of resistor did you install ?

 

hey techrep its a 2007 4.6 base model..i replaced the flat looking plug in resister i have normal dials with 4 positions

 

'You didn't answer all my questions... what brand resistor did you install ?

 

I INSTALLED AN EBAY JOB PROBABLY CHINESE...lol

 

In that case I would try another... that would explain why it goes batty when you plug it in and why it works with direct 12vdc on the motor. Try a Bosch or Wells brand..

 

I EXPERIMENTED i ran a hot wire from the plugto motor in truck with exterior ground i ran straight to the battery instead of one on the plug....it fired right up full speed but would not work on the speeds just went full blast

 

The blower motor resistor is in between that which you eliminated running the hot wire.. controls the motor speed with a set of resistors.

 

i ran the hot wire from the plug itself.....the ground i ran a new one right to negativeon battery touched it to ground on motor....seems to me the ground is bad either on motor....or on plug...im new to checking ohms and dont understand this multimeter yet just bought a klein tool mm600....

 

You have a bad ground. Remove RH kick panel and inspect.