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sprinkles08
sprinkles08, ASE Certified Technician
Category: Jeep
Satisfied Customers: 21604
Experience:  Chrysler/Dodge/Jeep Master Certified, ASE Master and Advanced Certified, Trans and Hybrid Specialist
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I have a 1998 TJ Wrangler with the 2.5 Manuel trans and I'm

Customer Question

I have a 1998 TJ Wrangler with the 2.5 Manuel trans and I'm having a problem with my heater, I have checked the blower motor, heater core, resistor, vacuum lines, coolant levels, burped the system, and the controls. (probably some other stuff I'm forgetting as well).
So my problem is that the air that comes out of my vents is not very strong, It is actually very weak although I can feel it trickling out. The blend door seems to be working since if I change the location on my controls the air only flows through the selected vents and not the others but is still very weak. I took the intake to my blower motor off and made sure it was all clean and not clogged up in there as I do go off road. I don't know what to check next and would appreciate a second opinion.
Submitted: 1 year ago.
Category: Jeep
Customer: replied 1 year ago.
I also had my water pump tested.
Expert:  roybelding replied 1 year ago.

good evening my name is ***** ***** I will assist

does the blower motor speed up and slow with command from the switch???

Roy

Customer: replied 1 year ago.
Yeah all speeds are functional.
Expert:  roybelding replied 1 year ago.

ok, first, I would make sure the wheel on the blower is spinning the same speed as the motor. if it is, then there is a dust issue either with a door directing wrong air or a possible restriction in the ducts.

Roy

Customer: replied 1 year ago.
I took the heater suitcase out today and it was all clean, I also made sure that the heater core wasn't covered in dirt and grim preventing air from flowing through. I also took the blower motor out and wired leads straight to my battery to test it and it spun fine. And I've already tested the blend doors, I had two in there but they move in the full range and are clean. They also direct the air exactly where my dial says they should.
Expert:  roybelding replied 1 year ago.

ok, what is the voltage at the blower motor??

Roy

Customer: replied 1 year ago.
I'm not sure.
Expert:  roybelding replied 1 year ago.

check the actual voltage it should be at least battery voltage

Customer: replied 1 year ago.
I have no way to test it right now
Expert:  roybelding replied 1 year ago.

ok, I will wait until you get a voltmeter. I am worried that there is low voltage at the motor resulting in low air flow

Roy

Customer: replied 1 year ago.
Can we just assume that it's good? The squirrel cage is moving about as fast as I've ever seen em move.
Expert:  roybelding replied 1 year ago.

I am trying to help you and you want an answer for the issue. I am not there and need to get these checks done in order to help.

Expert:  roybelding replied 1 year ago.

how are you making out??

please dont forget to rate me as it is the only way I get paid for my efforts

Roy

Customer: replied 1 year ago.
I put in a brand new blower motor, resistor, and blend door actuator this morning. Still having the same problem
Expert:  roybelding replied 1 year ago.

why did you do that???

did you check the voltage as I asked???

Roy

Customer: replied 1 year ago.
No I did not, I don't have a voltage tester and my boss ordered the parts for me and told me if they dont work that he would send them back so it didn't cost me anything. So we got all the parts from napa last night and I put them in this morning. Still having the same problem.
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

If you've had the heater box removed and there are no issues blocking airflow then the problem either has to be the blower motor running slowly, backward, or there could be a blockage inside the dash. A blockage in the dash wouldn't be likely.

The problem is most likely electrical, either a poor power or ground to the blower motor or the motor itself. I've seen many issues with aftermarket blower motors, often spinning backward.

Was there any corrosion on the blower motor connector terminals?

Customer: replied 1 year ago.
No corrosion on the plug or ground, ill trace the live in the morning. But I put a new blower motor in this morning too.
Expert:  sprinkles08 replied 1 year ago.

I did note that you replaced the blower motor, but as I mentioned I've seen many issues with aftermarket blower motors. If there is no blockage in the heater box then the issue is the blower motor or a poor power or ground to it.

Customer: replied 1 year ago.
I apologize for the the delay sir, I have been getting pulled into work early and have not had time to look further into it. I should have time tonight and ill let you know how it goes.
Expert:  sprinkles08 replied 1 year ago.

Ok.

Customer: replied 1 year ago.
I checked the plug and traced the wires as far as i could and found no corrosion and no other problems. The only thing that I can think of is that maybe it started to corrode inside the insulation and hasn't broken through it yet. My buddy has some sort of tester that you run up and down the lines and its supposed to tell us if theres a bad connection in it. Should I try that?
Expert:  sprinkles08 replied 1 year ago.

Do you have an incandescent test light or a headlamp bulb and some jumper wires?

Customer: replied 1 year ago.
I have the bulb and wires
Expert:  sprinkles08 replied 1 year ago.

Attach each jumper wire to one terminal on the bulb. Touch the other end of each jumper wire to the positive and negative battery posts and note the brightness of the bulb.

Unplug the blower motor connector and connect one jumper wire to each terminal. Turn the key on and blower motor on. Is the bulb as bright as if connected to the battery?

Customer: replied 1 year ago.
it is
Expert:  sprinkles08 replied 1 year ago.

Power and ground are likely ok then, leaving the blower motor or a restriction as the possible causes.

Does it have normal airflow when set to recirculation?

Customer: replied 1 year ago.
I don't have a recirculation button.
Expert:  sprinkles08 replied 1 year ago.

Do you not have a/c?

Customer: replied 1 year ago.
No I do not.
Expert:  sprinkles08 replied 1 year ago.

Can you use jumper wires to apply power and ground to the blower motor to see if it blows stronger? Set the wires up in one direction and check, then reverse polarity and check that way also.

Customer: replied 1 year ago.
Ive done that. Reversing the polarity mad the squirrel cage spin the wrong way
Expert:  sprinkles08 replied 1 year ago.

I need to know how the airflow feels with the jumper wires in each position and as opposed to when it's plugged in and turned on.

Customer: replied 1 year ago.
The air feels the same, when reversed I get no air at all.
Expert:  sprinkles08 replied 1 year ago.

The problem has to be the blower motor itself or a restriction in the heater box then. I'd recommend either a Mopar blower motor or the heater box is going to need to be removed and disassembled again to see what is going on as something has been missed.

Customer: replied 1 year ago.
Well I'm sure I didn't miss anything I shopvac' evey piece individually and literally had the box open in my house. I'll try a mopar blower motor it will probably be a few days before I get it
Customer: replied 1 year ago.
You're probably starting to see why iam stumped though, because I have gone through everything multiple times. I do this for a living and it should be working
Expert:  sprinkles08 replied 1 year ago.

Applying power and ground with jumper wires rules out an electrical issue and leaves only the motor itself and an issue in the heater box. If you're confident there isn't anything wrong in the heater box then I'd recommend a Mopar motor. I wouldn't consider using an aftermarket blower motor except in the event of emergency.