Top 10 2002 Jeep Grand Cherokee Questions & Answers

the relay is dirt cheap at the store (8-12 dollars), the relay is easy to find. on top of the engine area back near the firewall is a small to medium sized black box with a snap up lid...there are relays just sitting inside of it, you want the one with 3 prongs going across the bottom and 2 prongs going front to back on the bottom. it's a big square piece that just pulls out. the wiper fuse is kinda a pain to get to busy easy to replace... it's a really big silver metal cased fuse on your fusebox closest to the floor... be careful because if the wiper fuse is bad, it may be hot as hell to touch so take care when grabbing it. any auto store will have one. if neither of these fixes work then you need to check the motor wheel that connects to the wiper arm rods under the vents where the washer lines run down from the arms... sometimes the pins that connect the arms to the wheel snap off which make the wipers stop. worst case is the motor itself went bad. hope this helps

I will post it in 2 different posts because its too long DB

HEATED SEAT SYSTEM
Individually controlled driver and passenger side electrically heated front seats are available factoryinstalled optional equipment on this model, when it is also equipped with the power seat option. The heated seat system allows both the driver and the front seat passenger the option to select one of two seat heating ranges, Low or High, or to turn the individual seat heaters OFF using the heated seat switches located in the center lower bezel near the bottom of the instrument panel center stack. The heated seat switch circuit operates on ignition switched battery current supplied through a fuse in the junction block, only when the ignition switch is in the ON position.

The heated seat system consists of the following components

• Heated seat elements
• Heated seat sensors
• Heated seat module (or memory heated seat module)
• Heated seat switches.

The heated seat system also relies upon resources shared with other electronic modules in the vehicle over the Programmable Communications Interface (PCI) data bus network. The PCI data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, internal controller hardware, and component sensor current loads. At the same time, this system provides increased reliability enhanced diagnostics, and allows the addition of many new feature capabilities. For diagnosis of these electronic modules or of the PCI data bus network, the use of a DRB scan tool and the proper Diagnostic Procedures are recommended.

The electronic modules that may affect heated seat system operation are as follows:

• Body Control Module (BCM) - Refer to Body Control Module in Electronic Control Modules for more information.
• Heated Seat Module (HSM) - Refer to Heated Seat Module in Electronic Control Modules for more information.
• Memory Heated Seat Module (MHSM) - If the vehicle is equipped with the Memory System, refer to Memory Seat Module in Electronic Control Modules for more information.

Refer to Power Seats Premium I/III in the Contents of Wiring Diagrams for complete circuit diagrams. Following are general descriptions of the major components in the heated seat system.

The heated seat system will only operate when the ignition switch is in the ON position, and the surface temperature at the front seat heating element sensors is below the designed temperature set points of the system. The heated seat system will not operate in ambient temperatures greater than about 41 °C (105 °F) . The front seat heating elements and sensors are hard wired to the Heated Seat Module (HSM) or the Memory Heated Seat Module (MHSM).

The heated seat switches are hard wired to the Body Control Module (BCM). The BCM monitors the heated seat switch inputs, then sends heated seat switch status messages to the HSM or MHSM over the Programmable Communications Interface (PCI) data bus. The HSM or MHSM contains the control logic for the heated seat system. The HSM or MHSM responds to the heated seat switch status messages, ignition switch status messages, and the front seat heating element sensor inputs by controlling the output to the front seat heating elements through integral solid-state relays.

When a seat heater is turned ON, the sensor located on the seat cushion electric heater element provides the HSM or MHSM with an input indicating the surface temperature of the seat cushion. If the surface temperature input is below the temperature set point for the selected Low or High heated seat switch position, the HSM or MHSM energizes the integral solid-state relay, which supplies battery current to the heating elements in the seat cushion and back. When the sensor input indicates the correct temperature set point has been achieved, the HSM or MHSM de-energizes the solid-state relay. The HSM or MHSM will continue to cycle the solid-state relay as needed to maintain the temperature set point.

The HSM or MHSM and the seat heater elements operate on non-switched battery current supplied through the power seat circuit breaker in the junction block. However, the HSM or MHSM will automatically turn OFF the heating elements if it detects an open or short in the sensor circuit, a short or open in the heating element circuit causing an excessive current draw, or when the ignition switch is turned to the OFF position.

See the owner's manual in the vehicle glove box for more information on the features, use and operation of the heated seat system.

I WILL POST THE REST

102417

Most common cause of this is crank position sensor. however there are several equally good reasons as well. Have your codes checked with a scan tool, check your battery voatage (should be 12v or better) and listen for fuel pump running in tank with key on.
There are individual component tests you can make with a decent volt/ohm meter. Test for cps is that between b&c terminals there should be no connection (continuity) same reading as you get with meter turned on and test leads not touching anything. You can find instructions in most manuals including vehicle -specific ones such as haynes.
This is not a solution. unless someone gets lucky and guesses correctly, only proper testing will get you an accurate diagnosis!
good luck!

Poor grounding can cause many of the conditions you have listed. When checking power with a volt meter, this goes unnoticed because the meter does not draw enough amperage to cause the bad connection to break contact. Your battery is grounded to the engine block and also has a small lead to the fender. Many components have individual ground leads as well (including most computers) I would check all ground leads and clean the contact surfaces with sandpaper or a wire brush. Adding an additional ground wire is a good idea as well. Don't forget that the dash board frame must also provide a good ground as well.
Many times this is all you need to do...sometimes though, control modules can be damaged because in having a partial ground, they build up heat, due to additional resistance in the circut.
This may or may not cure your problem, but it's worth checking out. Grounding is often overlooked, especially if it has not completely broken down.

fuse #6 15 Amp Lt. Blue Park Lights (tail lights and front marker lights) Inside fues box

http://www.wjjeeps.com/speed_sensors.htm

Put a sheet metal screw between the mirror and mirror body below the mirror. This will allow the mirror to still break free and swing if you hit something kinda hard, but will keep it from moving freely. There is no other way to tighten it. It's just a case of the spring becoming fatigued.

Not a bad gasket, as there is no gasket. The heater core has developed a small leak and needs to be replaced or repaired. This is a big job, as the entire dash has to come out of the Jeep. The cost of the part is $77 at autozone, but the labor is several hours at a good shop. We have the procedure and can send it if you would like to do this job yourself. Just let me know.

Keep in mind that all this information is in the WJ owners manual...



Image: WJ Junction Block (under dash, left of steering wheel)




Image: Grand Cherokee fuses 1999-2004




Image: PDC (Power Distribution Center, under hood)

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I have the same issue. I took the flasher relay out, inspected the pieces for any hairline fractures on the circuit board, nothing it was clean. On my jeep, the turn signals always work in the Spring, Summer, Fall months, but as soon as Winter hits I loose my turn signals. Also, I know it is temperature related because I drive around for a half hour and the signals work again. It is really strange, I think the issue is somewhere in the ground wire, I will be checking that next and will post any new information. Anybody else who has had this issue and correlation I would certainly like to hear about any solutions. Thanks