FM Radio Reception / Blower Motor

[96GS#007]

'96 Jeep Grand Cherokee Laredo with 126,xxx miles
AM/FM Cassette
Manual HVAC

I have two unrelated issues (one is 6 months old, the other happened today) I'm trying to resolve.....

1st....
My radio (without warning) stopped receiving FM radio stations on the way home from work today. The AM band still works perfect, very clear reception. Since the AM is perfect and the FM death was sudden, I'm guessing the radio is the culprit vs something like a broken/loose antenna cable. I'll pull the radio tomorrow and make sure the coax is connected but I'm not holding my breath. Comments?

2nd...
About 6 months ago, the "High" speed setting for the HVAC blower motor began working intermitently and then stopped working completely.
- The Low and both Medium speeds work perfectly
- I got a hold of a spare HVAC dash unit and there was no change
- Swapped in a spare blower motor to no avail
From looking at the schematic in the Service Manual, it appears the voltage bypasses the resistor for "High" speed, so that eliminates it from the equation. Any idea where to look for the ground? The Factory Service Manual wasn't real clear on connector locations.

Thanks

[Jeep01]

I had the same problem with mine.

It was the connector to the Resistor Module.

I'm not sure if you have the same one as my 01 Jeep Cherokee.

[96GS#007]

Originally Posted by Jeep01

I had the same problem with mine.

It was the connector to the Resistor Module.

I'm not sure if you have the same one as my 01 Jeep Cherokee.

Thanks.

I'll check the pins for corrosion and then chase the wires back to the switch. I hate electrical problems

[greasefingers]

resistor pack is what you need

[96GS#007]

Originally Posted by greasefingers

resistor pack is what you need

On thought on the "High" setting it bypassed the resistor?

[Rccarps2]

From the FSM

BLOWER MOTOR RESISTOR
BLOCK
DESCRIPTION
Models with the standard manual temperature
control system have a blower motor resistor. The
blower motor resistor is mounted to the bottom of the
HVAC housing, under the instrument panel and just
inboard of the blower motor. It can be accessed for
service without removing any other components.
OPERATION
The resistor has multiple resistor wires, each of
which will reduce the current flow to the blower
motor to change the blower motor speed by changing
the resistance in the blower motor ground path. The
blower motor switch directs the ground path through
the correct resistor wire to obtain the selected speed.
With the blower motor switch in the lowest speed
position, the ground path for the motor is applied
through all of the resistor wires. Each higher speed
selected with the blower motor switch applies the
blower motor ground path through fewer of the resistor
wires, increasing the blower motor speed. When
the blower motor switch is in the highest speed position,
the blower motor resistor is bypassed and the
blower motor receives a direct path to ground.
The blower motor resistor cannot be repaired and,
if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR BLOCK
For circuit descriptions and diagrams, refer to the
appropriate wiring information.
WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS,
DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE
THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM
CAPACITOR TO DISCHARGE BEFORE PERFORMING
FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the
blower motor resistor.
(3) Check for continuity between each of the
blower motor switch input terminals of the resistor
and the resistor output terminal. In each case there
should be continuity. If OK, repair the wire harness
circuits between the blower motor switch and the
blower motor resistor or blower motor as required. If
not OK, replace the faulty blower motor resistor.


Ryan

[FreedomCherokee]

I'm a little confused on exactly where the resistor is located. So is it inside the cabin on the passenger side? Or driver's side? Anybody have any pics/diagrams?

Thanks!

[Rccarps2]

Blower Motor Resistor Removal


REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Depress locking tab and unplug the wire harness
connector from the blower motor resistor.
(3) Depress locking tab and unplug the resistor
connector from the blower motor.
(4) Remove the 2 screws that secure the blower
motor resistor to the HVAC housing.
(5) Remove the blower motor resistor from the
HVAC housing (Fig. 16).

untitled.jpg

ps. it is in the passenger footwell. The view in the pic is upside from what you will see when you look under the glovebox.



Ryan

[FreedomCherokee]

Thank you so much!!!

[96GS#007]

Thanks for posting Ryan. I'm in the process of moving to Seattle, WA from St. Louis, MO and all of my manuals and such are on a moving truck in transit.

As mentioned in the write-up, the resistor is bypassed when the switch is set to high, so it looks like I have a wiring issue to chase once we're moved in

[FreedomCherokee]

Originally Posted by 96GS#007

As mentioned in the write-up, the resistor is bypassed when the switch is set to high, so it looks like I have a wiring issue to chase once we're moved in

I was having the same issue, with the hi setting not working. I just did some investigating, and discovered that there was a wire loose in the connector that is about 8 inches from where the blower motor is. The dark green wire is the one that goes to the hi fan setting. You might check that. If I wasn't descriptive enough, I can probably get out there and take some pictures.

[96GS#007]

Originally Posted by FreedomCherokee

I was having the same issue, with the hi setting not working. I just did some investigating, and discovered that there was a wire loose in the connector that is about 8 inches from where the blower motor is. The dark green wire is the one that goes to the hi fan setting. You might check that. If I wasn't descriptive enough, I can probably get out there and take some pictures.

Freedom Cherokee nailed it. I found that I could jiggle the wire by hand and the blower motor would blow on high. Jiggle/tug on the wire again and the blower motor would stop. In my case, the wiring was stuffed so far up/behind the dash that I had to remove the glovebox and trim to reach it. Ince I did that, I disassembled the connector, cleaned up all the connections, put it back together, and it now works as designed We're having a house built which means we're stuffed in an apartment, most of my tools are in storage, and of course no garage, all of which adds to the challenge

I have a radio on the way with a CD player to replace the current one that's lost its FM function. Hope to have that later this week or early next week.

Thanks to all that took the time to reply