well, after getting the dash bolted back in Friday nite, I decided on Sunday to see if everything worked. it did not. the blower doors worked fine, but the blower motor doesn't. this is a new blower motor and something told me to check the wiring. since the new blower motor came without the end connector on it, I took the old one and reused it (not fun). and when I had put it back together, the wires were crossed. could trying to turn it on with the wires crossed cause it to not turn on at all? or is this something else?
What happened when you turned it on with the wires crossed? Hear and electrical arching or popping noise? Good chance you blew the blower motor fuse and check it in the passenger side floor kick-panel fuse box.*
It should be noted the blower motor high-speed is turned on via ground and by-passes the blower motor resistor since it uses so much power. The other speeds are wired through the blower motor resistor.
* edit/correction. After checking the FSM the blower motor fuse is #7 in the PDC which is the fuse/relay black box on the passenger fender well of the engine compartment.
What wires did you cross? AFAIK the blower motor is a standard DC motor. Switching the power and ground should just make it run reverse rotation. Have you checked the wires with a multimeter to be sure you're getting power and ground?
ok so I just checked the #7 fuse that uniblurb mentioned, its good. I found two other smaller fuses inside that go to the HVAC system they were good also. I pulled apart the plug between the resistor module going to the motor itself. and the voltage never went up by more than half a volt. I checked it on AC as well as DC and with power on and the blower turned on, the voltage never really went up. is this the resistor issue? or is it something else? the blower doesn't come on regardless of which speed you have it on.
Do you have the manual or ATC (auto temp control) system? On the ATC there's also a blower motor module which can go bad.
Why did you replace your blower motor in the first place and was your old one not working at all?
With no voltage at the motor you may very well have a wiring problem. There's a large plastic wire connector up under the edge of the dash and believe it's just to the left of the glove box. See if you can pull it down and disconnect it. There's a pin in there which sometime fries/melts disconnecting power.
I've also seen the blower motor speed switch behind the HVAC controls melt down. Remove the bezel and pull the control unit out to check. Believe it's all metal clips on the upper and middle part of the bezel but may be a couple hidden screws on the bottom where you have to remove the lower dash molding to get to them.
Let us know what you find and good luck!
Edit: here's a photo of the plastic connector I was talking about and guess it's behind the glove box. You can see it melted but this may just be for the high speed where it bypasses the resistor. Still wouldn't hurt to check but you may want to check the blower switch first and see if it's getting power.
I dont have ATC on my jeep and I do agree its something in the wiring. I replaced the motor because I had to replace the evap core, so when I took out the black box, I replaced the heater core, evap core, and blower motor. I have the dash bolted in, but all of the controls are out. the connector you are talking about....I have a large white connector at the glove box location. I will look to see if I can find a schematic for that connector so I can trace it. thanks uniblurb for the quick responses. you have been most helpful so far.
Ahh..the fun job of removing the HVAC box and I've replaced the same parts you have on my 96 4.0.
I'd make sure you have all your grounds/straps in place you may have had to remove with the dash/box. This is particular important for the blower motor since the high speed is turned on via ground and the lower speeds are also turned on through the ground through the resistor.
You may just have a connector somewhere which isn't making full contact. Good luck and keep us posted.
update. so I finally got 12V showing up at the connector going to the fan. I don't know for sure if this mattered, but I hooked up all 3 connectors to the heat/AC panel. when you turn it to cold or hot, you can hear I assume one of the doors moving, before I didn't have that switch hooked up. if this mattered, then wow, no wonder I couldn't figure out why 12V wasn't going to the fan. NOW.. to determine if the connector is bad or if the motor is bad. its a new motor, but for some reason.. 12V isn't showing up at the fan side of the connector. I will say that this new motor did NOT have a connector on it, so I took te old connector of the old fan and resoldered it onto the new one and it wasn't the prettiest thing ever.
Guess it does matter to have all the connectors to the control switches connected.
Did the new blower motor have any instructions saying which wires are power/ground? Sometimes you can't trust the color coding to be the same as OE. I've heard of some jumping the motor directly to the battery to see if it works. But don't do this with the harness/connector still connected and knowing which wires are which helps.
update. so I chopped off the connector on the motor side. thinking it was the connection that was bad, I went out to look for a new one. no such luck. and then the wheels started turning. I said to myself.. lets put the connector back on without the motor. and viola. 12.5V. soo NOW i'm thinking hmm is this motor bad?? since I just got it a week ago, i'm just gonna go back to NAPA and say give me a new one this one is bad. I called and asked if they would test it, they said they couldn't. soo new motor it is.
I had mentioned jumping the blower motor to the battery Josh with harness disconnected. But how do you know which wires to touch to the battery terminals?
I know you said if the wires are switched it will just turn the motor backwards but I can't remember how many wires are on the motor? Guess it doesn't matter how you connect it if he's returning it anyway.
According to the pictures on RockAuto it's just two wires. Looks like the ones you have to cut and wire yourself (no plug included) have an orange and a black wire. I'd put good money that the orange one goes to +.