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Blower motor stopped working...

gw204

NAXJA Forum User
Location
St. Leonard, MD
Was flushing out the cooling system in my '00 this afternoon by disconnecting the top radiator hose (ran it to a bucket) and filling the radiator via the cap while the engine was running. I had the heater on high while I was doing this and when I shut the Jeep down I noticed it was no longer blowing any air. It won't blow on any setting. High, low, A/C, heat, defrost... So, I started checking fuses thinking I may have gotten something wet but they all seem to be fine. I don't think it was a failure of the motor itself as it never gave any signs of going out. I found reference to the resistor, and how the fan should still work on high so I don't think it's that either.

I did get overflow from the radiator fill port and some from the inlet on the pass side, but I didn't see any electrical components in the path of that water. I think I also splashed some on the connectors against the inner fender by the air box, but it wasn't a lot.

Any ideas? I'm going to pull the blower and check it next...

Thanks.
 
Just jump the blower motor. Or use a test light. The blower motor switches are VERY prone to giving up the ghost. They also sometimes result in cool jeep fireballs.
 
Thanks for the suggestions guys. Dumb question though... Where the heck is the plug? I looked for it for a minute or two, but came up empty.
 
Got the wire, but it tucks behind the firewall and there's pretty much no slack on it ,and no connector is accessible. Any chance I can get to it by removing the wiper cowling?
 
Lol? they should come out of the firewall... anywho god made test lights with sharp tips to do cool things like poke insulation.
 
Looking in the 2000 FSM, the plug is right there on the motor. There is actually no wire out of the motor. The wire plugs into the motor right at the motor. Hopefully you can uplug that. Hope the motor is good. THe FSM says you need to evacuate the system and remove the accumulator / dryer to get the blower motor out.
 
Got the plug out...what a PIA. Thanks winterbeater!

Looks like I'm not getting power to the blower motor. What to check next? Recheck the fuses and get a look at that resistor?
 
pull ur HVAC controls out of the dash and see if the plug for the switch is burnt Odds are it is. Every one I have seen is burnt or melted. At junk yards there either burnt melted or gone.
 
All the plugs look good. I can hear the system try and change functions when I move the middle switch. I verified power in the connector for the fan speed switch and will try to jump the fan via that connector tomorrow once I get the fan connector plugged back in. Access to that connector is nearly impossible. Whomever laid that out should be shot...
 
Your welcome I'm not sure whats next on the 00
Did you test light the switch? the fuse? you might have to trace it from the switch until you find where there's no juice. might have fuse-able links somewhere
 
Just keep tracing down the line for the high speed fan, as that bypasses the resistor. Are you SURE the fuse is good. Have you popped it out to look at it. The reason I push this it that I had one of those LED fuse testers that came free in an assort of fuses that told me the fuse was good. Two weeks later, I figured out that it was actually burnt, but a small back current in the system tricked it. Checking with a voltmeter showed me that I had 12 V on one side of the fuse and 1.5 on the other.
 
So here's what I have so far...

Fan on low, function switch set to off and 12v+ to the ground cable at the blower motor. Voltage stays the same no matter what I set the fan speed switch to. Voltage drops to 0 if I set the function switch to A/C, heat or defrost. If I disconnect the blower resistor, I still get 12v+ to the ground with the function switch set to off, but only on the high fan speed setting. All other fan speed settings get 0 volts to the ground cable as do the A/C, heat and defrost settings. That sounds completely wrong to me... I'm thinking it should be the exact opposite and I should get the 12v+ to the green wire going to the blower motor.

If that resistor is burned out (which I don't think it is) will there be any visual signs? Any way to test it? If it is toast, would it cause the above.

Which wire is for the high speed fan setting? I couldn't figure it out by probing the connectors on the back of the speed switch.

Fuse looks good visually.
 
So here's what I have so far...

Fan on low, function switch set to off and 12v+ to the ground cable at the blower motor.

If this is the case, then the ground is bad. read resistance (with the battery disconnected!!!) between the ground cable and a piece of metal on the frame/body nearby. It should be less than 1 ohm, but I am betting it is higher that that. If it is high, find where the wire attaches to ground and repair...

if there is 12V on the ground, then the motor sees no difference in potential when you apply 12V to it via the switch. Clear as mud?
 
I'm going to go out on a limb and assume the '00 is wired similar to my '99. If so, have you checked the relay for the blower motor. It's real easy to get to. Just flop the glove box all the way down and it is right there. Pop it out of its holder and test it to make sure it is working correctly. Mine is pretty much toast but I can still get it to work if I tap on it a few times to help get the relay to click into position.
 
Thanks for the info on the ground and relay. I'll check both of thode out. BTW - how do you check a relay? I'm not real good at this electrical stuff...
 
Apply ground to pin 86 and +12V to pin 85. (Even a little 9V battery will work as it only takes about 8V to activate the relay.) You should hear a click as soon as the circuit is completed. No click means the relay is bad.

If you hear a click, test the continuity between pin 30 and pins 87 and 87a. Pin 30 should have continuity with pin 87 when voltage is applied to pin 85. Pin 30 should have continuity with pin 87a when no voltage is being applied to pin 85. (If the relay only has 4 pins, don't worry about 87a.)

Mine works most of the time, but every so often it sticks. The pins are also discolored from the years of use. It's time to replace it, I just haven't gotten around to it yet.
 
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