It's getting hot here in AZ and I recently had my a/c in for a tune up. Air blows nice and cold but stopped suddenly. I find that my blower motor has taken a turn for the worse with a strange noise. So I order a new one, remove the basket and put on new motor, plug it in and test it before I install it. It won't spin. So I replace my old one and it spins but not very well and makes the same noise. I return the new blower for another a the auto parts store only to find out that that one doesn't spin either. I am guessing it's a wiring issue. There are no frayed wires and everything is tight.
Also the block box just under the dash on the passengers side has been getting very hot, so hot that even at night it's almost like I have the heater on full blast. I tried adjusting the switches back and forth and that isn't helping. Doesn't the heater core and condenser unit sit in that box. I know they do on the 97+. Can the condenser get that hot that it's almost too hot to touch?
On a side note, I have replaced the radiator with a new one. I have flushed the system several times with Ironite Thoroflush a couple of times. It's always brown gunky water when flushed. Not sure if the system is clogged and I don't have a gauge only a dummy light so I don't know how hot the water is getting up to.

 

If the fan blows when switched to high, it is the blower motor resistor has failed. When the switch is on the highest setting it bypasses the resistor.

 

Could that resistor be the reason it is getting so hot in that box that is where the resistor connects to?

 

yup

 

So I got a MAP sensor in and a blower motor resistor in today and installed them. I haven't driven around long enough to not notice how hot is was getting. I kicked on the A/C and it almost killed my motor. It shakes really bad. I just had it rebuilt or more freon put into the system. I blows cold but only in park will it not kill the motor and it doesn't blow very high. It's on the high setting but it feels like its on the low setting. What would cause it to kill the motor and how come the blower motor doesn't kick out a higher velocity blow?

 

Start by checking the wiring to the fan selector switch on the dash. The switch and/or wiring connector is know to fail and melt/burn. My Jeep had the connector melt. I did not replace the connector, I attached thermal connectors to each wire and replaced the switch with a new one. Make sure, if you do this, that you know which wire goes to which terminal on the switch. Make a drawing and take pictures for reference.

 

The '96 Fan wiring is an electrical engineers nightmare, all current flows through all the wiring, switches, etc including the ignition switch,
eventually something turns to toast, usually caused by a dodgy fan drawing too much starting current (there is a fuse)

It could be burned anywhere

If it works properly on "full speed" you can do what I did and add a relay for each speed (other than full speed), problems solved

If it doesnt work properly on full speed, the problem is further back in the wiring or switches somewhere

the wiring around my resistor pack was melted, it needs to be in the air tunnel so it gets cooled by the airflow from the fan

 

I heard the 96 was a bastard year but I didn't think it would lead to this. Other than pulling the dash apart, how else would I check for faulty wiring? I have a draw somewhere as it eventually kills my battery, so I know I need to figure that out. But I believe this is something totally different. My resistor wiring was intact and not frayed or broken. Before my a/c fix there wasn't any issue with the blower motor sending out the amount of air it should. Even though it was warm, it was great in the cooler months. I have not tried turning on the heat full blast to see what happens with the motor. Also, when the a/c is on it's really loud and the jeep shakes. I am not a wiring guy but I guess I will have to figure this out somehow.

 

It was the same for at least 94-96, I dont know before that

I dont understand why your whole Jeep shakes, unless the A/C compressor or clutch is seized, which you can check by observing under the bonnet with the system running

If the fan itself is noisy, it means the internal bearings or bushes are worn. You have changed fans so I doubt that is the issue (now)

An Auto-electrician should be able to give a likely diagnosis in a few minutes

I would proceed with a few diagnostic checks, and if you cant figure it out, take it to a pro, thats what they do for a living

 

The coincidence of the blower motor acting up after your a/c "rebuild" may not have anything to do with the other. First, besides adding more Freon, what was done to the a/c system to rebuild it? As member AWG stated, you may want to visually inspect that the compressor clutch is engaging when you turn on the a/c. Also adding to much Freon is bad for the compressor and the system overheats.

Your electrical problem probably starts behind the dash...specifically the fan speed control switch.


Don't be surprised if you find this.

 

Thanks for the help. After looking around at a few videos, I see that switch you have in your picture is in your dash (or its a dash pic). Someone on youtube posted a video of the same looking switch, . I guess there are so many pre '97's out there that have this issue. Now I will check this issue out when I have some time today, tomorrow or this weekend and hopefully I will find the cure.
As far as the motor dying from the compressor coming on. When it was at the shop, the full diagnostics were done on it and no leaks were found, refrigerant was added and the system runs fine. I don't believe they drove it or they possibly would have dealt with the issue I am having.

 

I am not sure how I can check under the bonnet since it only shakes and shimmies while I am in drive. If it is clutch/ compressor related then I will take it in to the mechanic that did the original work.

 

There must be more than one fault existant

(imo) no part of the A/C & heater system can cause your Jeep to shake only when its moving

any fault finding, especially electrical, should be done systematically

I would still inspect the compressor and clutch for correct operation while the engine is idling (but parked)

As I said, I ran a (labelled) fused wire from the battery, through the firewall and placed 3 relays behind the kick panel to run each speed except 'Max" which is hard to access the wire, so I avoid running it on full

 

a

 

You may want to check your motor mounts......and transmission mount