Lj73 blower not working. (1 Viewer)

[NYccruzr1]

I have a 91 lj73 and the blower motor will not work. I don’t have a manual for the particular truck and am kinda shooting in the dark as far as what fuse, relay, etc to check. There were pieces of leaves and debris coming from the vents when the blower did operate. I’m assuming this is the cause. I have a 82 fj60, and when this happens I’m able to reset the blower relay. I did find the fuse box (drivers side left) and a couple of relays (drivers side above gas pedal). I checked all of the fuses ( visually) and all seem to look okay. I pulled and checked two relays, that I believe could be blower relays. These are different from the blower relay on the 60. This relay had no continuity across any of the prongs:

I replaced it with one that I know is good, and still no blower. I pulled the blower out and cleaned leaves and stuff out of the housing and vents. I found the blower resistor next to the blower when I pulled it out. This is what it looks like:

If you notice, I have a manual that covers some 70 series stuff. I checked this relay according to this manuals instructions, and it seems okay. So the fuses seem fine ( I think), relays might be good and the resistor seems to check out. Only other things I can think of is the blower switch and the blower motor it self.
Any thoughts and guidance here would be appreciated!

 

[NYccruzr1]

Questions I have are:
1) is the pictured relay the blower relay?
2) is there a fuse for the blower?
3) could I put 12 volts to the blower motor to see if it powers up? (This truck is diesel and has a 12 volt electrical system.

 

[876 Cruisers]

Good day.

The motor itself could have gone bad... it uses brushes and in this case could have been worn down and cause it to stop. Ive had to change the motor 2x on my kzj70 because of the brushes.

 

[NYccruzr1]

Thanks for the input. How’d you determined that the blower was bad?

 

[GTSSportCoupe]

I've had to change my blower motor too. (As well as the resistor unit). Seems par for the course on these trucks.

 

[876 Cruisers]

Thanks for the input. How’d you determined that the blower was bad?

I had a electrician check it for me. When he pulled it out the brushes had gone too far down and damaged something on the motor that the entire motor had to be changed instead of the brushes only.

 

[JuanJ]

Questions I have are:
1) is the pictured relay the blower relay?
2) is there a fuse for the blower?
3) could I put 12 volts to the blower motor to see if it powers up? (This truck is diesel and has a 12 volt electrical system.

Hello,

Regarding your questions:

1. Usually that relay is square in shape. The one in the picture may be the tail light relay.
2. The heater uses one of the four 30A fuses above the small ones.
3. You can function test the blower motor with a 12V source.

The blower motor makes a squealing noise when it is about to fail. Usually the brushes are the first to go and they produce a burning smell when they do. Ask me how I know.

The weak link here is the resistor. In time, the wire becomes brittle and breaks. The resin that holds the wire spirals becomes brittle and fails as well. As the wire breaks, variable resistance is lost and the fan operates at one or two speeds at the most.

Something similar happens to the control switch. It is another weak link of sorts. There is a detail, though: dirt builds up between the switch's mobile parts and block electrical continuity.

As a result, electrical continuity is lost and the blower motor does not receive power to operate.

Usually, either the control switch or the resistor fail before the blower motor does. From what you describe, it is possible that the resistor gave up the ghost. It is still available. You should replace it.

Rather than checking the motor, check the control switch for electrical continuity. It is good practice to clean it -using circuit cleaner- and then soak it in WD-40 (or a similar product) before and after the check. If cleaning does not help, replace it as well.

I am assuming you have disassembled at least part of the dash panel, so it should be easy to access.

Take the chance to lubricate the blower motor and replace the brushes before assembly.

Hope this helps.





Juan

 

[NYccruzr1]

Thanks!! I will go through all of this stuff. P

 

[NYccruzr1]

Thanks for all of the info on this! Turned out to be just the Breaker that was bad! I was initially looking at the wrong ones. Now if I could only source a repair manual for this truck........