1999 jeep wrangler heater blower

on high ?
bad fuses
Hi works, and others speeds dont, bad switch or blower resistor bad.
hot wire the blower motor , does it work now. bingo, bad controls.

This is 100% the Blower (Fan) Motor Resistor located near the Blower Motor.
This is a very common problem with Chyrsler, Dodge, Jeep and Plymouth. The key symptom is the Fan only working on High.
This is very easy to access and replace.

Let me know if this helped....

This is definitely 100% the Blower Motor Resistor.
Replace this and all speeds will work fine.
This Resistor is defined with 3 to 4 wires going into it, and is located adjacent to the Blower Motor.
It is easily access, removed and replaced.
I will post an additional comment on Part Number, Price and where available.
Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!

If you bypass the resistor pack and connect the motor directly to the fused 12v supply then the fan should run at maximum speed. If so, it's the resistor pack that's blown: a very common fault on a huge number of makes and models.

If the heater only works on the high setting, your problem is the heater fan resistor, not the relay.

blower motor resister has burnt out also check wiring going to your blower motor resistor these must have a good tight connection or they will burn if any sighns of being hot change the complete wiring pig tail to your blower resistor

I'd replace blower resistor, usually found under hood on firewall on passenger side, or on duct work, inside under dash on passenger side,close to blower motor.

Check the blower motor under the dash.(on right side put a 12v lead directly to the connection and if it works, the problem may be in the switch relay or resistor pack. (i've also heard of debris holding the fan from moving so if there is power there and motor does not run, remove & check first before buying a new unit.)

If the blower isn't working there are a few options.

Look in your fuse box under the dash on the drivers side and check the fuse that should be marked blower motor.

Next, The blower motor relay will be in a long rectangular box, near the battery. It will have a cover with a couple little clips that you have to squeeze to get it off. The lid of the box on the inside will have a diagram that tells you which relay is for the blower motor. If there is another relay with the same number on the back, you can swap it and see if the blower works. That's the easier way to see if that's the problem.

If it's none of those, then it's probably the blower motor itself. I would check to see if it's getting power before you replace it though. It could be the fan control switch on you dash too, but they don't go bad as often.

Check the blower motor resistor, I,m not sure where it is located on your vehicle most are on the firewall under the hood.