Blower motor still not working

[Eddie Greenlee]

I’ve done about all I can think of to do to get my blower motor back working. I’ve checked the fuse in the fuse box under the hood. I have replaced the resistor. I’ve replaced the switch. I replaced the relay.
I even took the blower motor out and tested it on a 12 V battery and it worked just fine. What in the world am I missing? ?? Thanks.

 

[macleanflood]

What in the world am I missing?

Voltage.

Trace all the wires in the circuit using the diagrams in the factory service manuals located in the resources section. Continuity and ohm tests.

-Mac

 

[B1Toad]

What year?? Which switch did you replace?

 

[Eddie Greenlee]

What year?? Which switch did you replace?

97 TJ : fan switch.

 

[B1Toad]

97 TJ : fan switch.

I haven't looked at a 97 but 99 and up use the ground signal to control all the blower speeds. Power is always at the blower whenever the key is on and the ground completes the circuit through the dash controls.

 

[Eddie Greenlee]

I haven't looked at a 97 but 99 and up use the ground signal to control all the blower speeds. Power is always at the blower whenever the key is on and the ground completes the circuit through the dash controls.

Thanks !

 

[jonny jeep]

In 97/98 models the motor is grounded and the positive supply is switched.

With what you've swapped on the positive side the only thing to check on that side of things is the supply which uses fuse 2 (40A) in the PDC and fuse 8 (20A) behind the glove box. If either of then are bad, the fan won't run on any speed as the supply from those is used to activate the relay for full speed, the supply that is switched comes from fuse 11 (40A) in the PDC. Fuse 2 should be fine as it also supplies the starter relay, and you haven't mentioned the Jeep not starting.

Ground for the motor is at G202. G202 location isn't shown in my 97 FSM, but in the 98 it shows as being grounded directly below the passenger side dash speaker.

 

[Eddie Greenlee]

In 97/98 models the motor is grounded and the positive supply is switched.

With what you've swapped on the positive side the only thing to check on that side of things is the supply which uses fuse 2 (40A) in the PDC and fuse 8 (20A) behind the glove box. If either of then are bad, the fan won't run on any speed as the supply from those is used to activate the relay for full speed, the supply that is switched comes from fuse 11 (40A) in the PDC. Fuse 2 should be fine as it also supplies the starter relay, and you haven't mentioned the Jeep not starting.

Ground for the motor is at G202. G202 location isn't shown in my 97 FSM, but in the 98 it shows as being grounded directly below the passenger side dash speaker.

Yes all fuses are in great shape and tested for continuity. If this is the ground, you’re speaking of I just tested it and it is grounded.

 

[jonny jeep]

That's the one. Only other thing I can think of would be loose spade connectors inside the blower motor plug causing a bad connection.

 

[Eddie Greenlee]

That's the one. Only other thing I can think of would be loose spade connectors inside the blower motor plug causing a bad connection.

That’s exactly what I was thinking. I know I tested it before I put it in but now I’m starting to second-guess myself. In the 97 it’s a little more pain in the rear because you have to take the battery out and you have to take the computer off the firewall just to be able to get to the screws to take the blower motor out, but I guess it’s time to do it again.

 

[Moglocker]

That’s exactly what I was thinking. I know I tested it before I put it in but now I’m starting to second-guess myself. In the 97 it’s a little more pain in the rear because you have to take the battery out and you have to take the computer off the firewall just to be able to get to the screws to take the blower motor out, but I guess it’s time to do it again.

It should be pretty easy to test the fan plug at the motor,with a simple test light,

 

[Eddie Greenlee]

That's the one. Only other thing I can think of would be loose spade connectors inside the blower motor plug causing a bad connection.

This does look a little sketchy. Going to see if I can move things around inside the plug and then try and test it.
I’ll have to hook the computer back up and the battery in order to test it .

 

[Eddie Greenlee]

It should be pretty easy to test the fan plug at the motor,with a simple test light,

This fan motor comes out under the hood, so I have to pull the battery in the computer to get to it. This plug is looking pretty sketchy though. I’m gonna try to move things around inside the plug so I can test it.

 

[Moglocker]

J

This fan motor comes out under the hood, so I have to pull the battery in the computer to get to it. This plug is looking pretty sketchy though. I’m gonna try to move things around inside the plug so I can test it.

View attachment 654527

Just test the wires right before the plug,simple test light ,reverse the polarity of the light to test ground.if they both check out,wire in a new plug.

 

[Eddie Greenlee]

I just tested both of the blower motors on a 12 V batterythat I have and both are working fine.
I cleaned the blower motor plug up and tested it for voltage with the Jeep running and the fan switch on. And there was no voltage. .

 

[Moglocker]

I just tested both of the blower motors on a 12 V batterythat I have and both are working fine.
I cleaned the blower motor plug up and tested it for voltage with the Jeep running and the fan switch on. And there was no voltage. .

Do you have power at the switch or the resistor?

 

[Eddie Greenlee]

Do you have power at the switch or the resistor?

I’ll check that out tomorrow. To cold here in MS to work outside tonight. Last night was 23. Not sure I’m ready for that.

 

[Eddie Greenlee]

I’ll check that out tomorrow. To cold here in MS to work outside tonight. Last night was 23. Not sure I’m ready for that.

I have no power/voltage to the resistor plug or to the switch plug. And my fuses

I’ll check that out tomorrow. To cold here in MS to work outside tonight. Last night was 23. Not sure I’m ready for that.

Hey y’all, I’m back up working on the Jeep this morning. Just wondering what the sequence is of voltage from the battery to all the components of the HVAC unit. So I guess from the battery it goes to the fuse box under the hood, then probably over to the ignition switch back to the fuse box in the glove compartment. Then, from the glove compartment fuse box over to the controls of the HVAC then to the blower motor? Is that anywhere close to right ?

 

[Eddie Greenlee]

Do you have power at the switch or the resistor?

Hey, I tested the plug going into the switch on the HVAC unit and I do have power from that plug so I know that it’s getting power to the switch. So does that mean the switch is not good? Even though I replaced it.

 

[Moglocker]

Hey, I tested the plug going into the switch on the HVAC unit and I do have power from that plug so I know that it’s getting power to the switch. So does that mean the switch is not good? Even though I replaced it.

Now check it leaving the plug,you should be able to bypass the plug with a jumper.on a 1997 there shotbe a blower relay behind the glove box,test for power