# Intermittent Power to Blower - 93 Sentra



## tkolarik (Sep 29, 2010)

I have a 93 Sentra XE with intermittent Blower operation. The Blower Motor itself is ok as is the Blower Mortor Resistor. When the blower runs it runs on all speeds and when fails to run, all speeds fail. Checked voltage to blower, no voltage when off. As precaution, replaced the relay even though this indicates it was not problem. Multispeed fan switch fully fuctional when operational. No voltage to switch when motor fails to run. There are two 15-amp fuses on fuse panel access door that say they are for BLOWER. When removed individually, blower continues to operate (during those times when it does operate)!

Any assistance in diagnosing the problem would be very much appreciated. Or, help in utilizing the Cigarette light accy as the power to the blower.

Does the power go to the relay first then to switch then to blower or from switch to relay to motor? Wires to Blower are large blue/red stripe and large blue/white stripe. Wire to relay are large Blue/white and three smaller wires blue/red, blue, black and blue/ green. The fan switch have large black, large Blue/White and small green/red, blue/red, blue/green, and blue/black. 

Thank you!


----------



## smj999smj (Jan 1, 2006)

The two 15 amp fuses power the blue/red wire to the blower motor. The wires from each fuse splice together into a single wire that goes to the motor, that's why you will have power when removing only one fuse; you will need to remove both fuses to remove power to the blower. Everything else is on the ground side of the motor (switch, resistor, etc.) which is obviously the blue/white wire at the blower motor. Voltage should be supplied to the blower motor (blue/red wire) at all times the key is in the "ON" position. If when the blower fails to operate, there is no voltage to the blower, then your problem lies in that power circuit. If there is power through the fuses, then the problem would be an open in that blue/red wire between the splice of the two wires from the fuse box to the blower harness connector. We know it's not a short to ground because it would blow the fuses. We know it's not one of the wires from the fuse to the splice, because we would still have voltage from the other wire. The splice should be close to the fuse block. So, find the open and repair the circuit if this is the case with your vehicle. I would not recommend using the cig light accy. due to the amperage required in the circuit (this is why they use the two fuse setup). If the blower is in-op and you do have power through the motor, check your body grounds for the switch.


----------



## tkolarik (Sep 29, 2010)

Thanks smj,

I have not checked the fuses when the blower is not running. I assume the hot side should be hot with the key on? I'll check on this. 

If the fuse is hot, I should be able to disconnect the blower and test with a voltage meter to the blue/red wire and a ground on the body and should get voltage with the key on? Maybe I should check this first then the fusebox.

If there is voltage at the fuse box, and if I cannot get access to the wires, can I just take the two off the fusebox and join them and run a new wire directly to the blower? I'm having a hard time getting to the wires behind the steering wheel.


----------



## tkolarik (Sep 29, 2010)

There is NO power to the two fuses when the blower fails to operate. Ignition on and not running. So where does the fuse box get it's power for those two fuses?

Thanks


----------



## tkolarik (Sep 29, 2010)

:givebeer:
There is a set of four relays mounted on the right side of the fuseblock (fusebox). The second one down is called the Blower Relay. becasue it was identical to the one below it, markings, etc, I swapped it and the blower worked just fine. So I purchased one at the local parts stores and so far all is working fine. As a matter of fact, things are workings BETTER! When I used to move the fan switch to the high position, the A/C light would go out. Now that doesn't happen.

Thanks to the forum for the Service Manual files without which I would not have been able to repair this myself!


----------

