Question91 GMC Jimmy V-6 ac/heater blower motor fuses keep blowing 25 amp and tried a 20 amp? Original blwr motor so could age be a problem and the cause?
thanks
Answerhi
Fuse feeds the selector switch and the selector switch feeds the current to the blower switch.
The blower switch feeds the blower motor resistor on low speed and medium speed.
The resistor feeds the High speed blower relay power (normally open) which feeds resisted current to the blower motor.
On High the leg on the High blower switch selector energizes the relay coil and closes the relay, allowing unresisted current to the blower motor (High speed)
Now Your problem could be in any of these parts OR the related wires.
I would pull the switches (selector and blower), they are VERY common for burning terminals and internally shorting out.
If it ONLY does it on high, I would suspect either the relay or the motor.
If it only does it on low or medium I would suspect the resistor or the relay or the motor.
Motor age should not be an issue, unless it has gotten wet or some other reason to suspect it (rodent infestation etc...)
I hope this helps.
JUST advice from experience.
Good Luck
Pawl
