jon71203

hey guys,
so i have no heat, air or defrost. when i turn the blower on i get nothing.
would this be the blower motor? any help would be great, the low temps and no heat are starting to wear on me.
thanks

jon71203

also, its not constantly without air/heat/defrost, occasionally while driving it will kick on for a minute or so and then stop again. would that make any difference? like possibly the relay/fuse?

JN88

i would test the blower motor first. by just putting power to it

jon71203

this may sound stupid, apologies in advance, but whats the easiest way to do that?

MtnHermit

Remove the motor, it's on the firewall - engine side. Use two leads from the battery terminals to the two terminals of the blower. Polarity doesn't matter. Does it spin?

XJ's have a tendency to fry the wires/connector at the blower resistor. It's under the glove box behind a small plastic kick panel. Worth checking.

jon71203

i know my resistor is bad, it doesn't blow on setting 3, hasn't for a good while.

the resistor wouldn't be causing the issue would it?

i'll test out the blower when i get home from work today

bigvig

Does it even SOUND like its blowing when you turn it up? I mean, if the motors gone you wont hear it blowing. That's the first way to test the blower motor. If its blowing and you have no heat then your heater core is probably plugged up.

CCKen

What year is this truck?

I gather it's an XJ Cherokee(?)

jon71203

its a 97 XJ Sport

no blowing sound at all when its not working, but like i said, occasionally it'll kick on for a minute or so and then go off again

RTorrez1

If it kicks on occasionally I would first make sure that the blower motor is operating correctly. You don't need to remove it to test it. Just run two wires from the battery to the motor and make sure it comes one and it stays running. Also check the connections since you have to unplug it anyways and make sure that the connections are clean and not loose also check the related wiring to make sure that there are no bare wires and noe brakes in the wiring.

77olds

The better way to test it is to get a test light. Unplug the connector to the fan motor. Clip the test light onto something bare metal, like a bolt. Turn the fan speed to 1, touch each terminal until the test light lights up. That's the terminal for fan speed 1. Repeat for each fan speed. All working correctly?

Now plug that back in, and unplug the connector to the resistor pack. Run the test all over again. More than likely, it's the resistor and wiring harness, that's common on a LOT of vehicles.

But in general when you're testing circuits, you start at the very END of the circuit and work your way backward to the switch. No need to remove anything from the vehicle to test it all, you just test the connectors and through process of elimination, you'll find the culprit.

RTorrez1

Not really true! when the resistor fails it will automatically default to only work on high and it will blow. The only reason for the resistor to cause it to completely stop working would be if the related wiring was completely melted and burnt. Since he said that it comes on at times I wouldn't think that would be the problem.

77olds

That's why you test things before you replace them. You need to check the circuit at every end to find what's going on... and yes, it could be the resistor or harness. Trust me, I've repaired enough of them to know what I'm talking about. They don't all behave the same every time they fail... but also note that I did not tell him to just go and replace them, but to TEST them.