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Don 'Mo Lurch'
Don 'Mo Lurch', Mechanic
Category: Jeep
Satisfied Customers: 20753
Experience:  Chrysler Warnty, Heavy Line Mech, Mobile Electronics. Sales, Installation & Repair for 30 years
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I am working on a 2000 jeep grand Cherokee. Power door locks

Customer Question

I am working on a 2000 jeep grand Cherokee. Power door locks and windows
Submitted: 9 months ago.
Category: Jeep
Expert:  Don 'Mo Lurch' replied 9 months ago.

I am working on a 2000 jeep grand Cherokee. Power door locks and windows
???

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did you have a question?
which engine & transmission is in the jeep?
2 or*****

Customer: replied 9 months ago.
Door locks, mirror, Windows inop. Checked the usual fuses wires etc. Only have 4.8v going to master switch. What relays at bcm and fuses are involved? If possible please advise commodity layout and schematic. I am shooting from the hip without knowledge of what relay supplies voltage to the drivers door switch. Has 4.0 i6 auto trans 4wd.
Expert:  Don 'Mo Lurch' replied 9 months ago.

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sorry for the delay............
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Greetings...... “Hi, I’m Don (akaCustomer and I look forward to helping you!”
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The Door Modules activate the Door Locks, Mirrors & Windows
Without the use of Dealer Scan Tool you are limited to test Voltage, Ground &checking connections
The Door Modules are located inside the Front Doors
Fuse "12" located in the PDC powers the Door Module
Test Voltage on "both sides" of Fuse 12 with Key ON
Here is Schematics

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Customer: replied 9 months ago.
That gets me closer . . . Still not able to complete the puzzle. So the driver door module is not getting 12v from the bcm. I don't have a diagram to know which fuse is fuse 12. Either case, I don't believe bcm is supplying adequate voltage. Wanted to verify I/O before tearing bcm out and replacing. Have you encountered anything like this on the past?
Customer: replied 9 months ago.
My mistake 12v from junction block not the bcm. Looks like there's nothing in-between j block and door module on the tan blue wire
Expert:  Don 'Mo Lurch' replied 9 months ago.

Still not able to complete the puzzle. So the driver door module is not getting 12v from the bcm

??

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No.......the BCM sends a DATA Signal in the form of a Ground.....Not Voltage
As stated, Fuse "12" powers the Door Module, in which the Door Module is responsible for sending Voltage + & DATA Ground
The circuit to the Windows & Door Locks will be "Reversal Rest at Ground"
meaning there are "2" wires that go to the Window Motor & Door Locks
One wire will have Voltage +.....one wire will have Ground - when the Switch is activated (up or down...lock or unlock)
When the Switch is moved to the other direction, the wire that had Voltage + now has Ground -.......The wire that had Ground - now has Voltage +
Typically it is the Door Module, but use of Dealer Scan Tool is needed to Test & Progam
You may want to try disconnecting Battery Cables & touch the Battery Cables together "BRIEFLY" then reconnect to see if that RESET the Module

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Customer: replied 9 months ago.
First I need to find the low voltage to the driver door master switch module. Any ideas of where it might be busted other than door jamb?
Expert:  Don 'Mo Lurch' replied 9 months ago.

Not sure what you are trying to confirm, as I posted the procedures

That would be the YELLOW / VIOLET
Click attachment

Expert:  Don 'Mo Lurch' replied 9 months ago.

will be off line for a bit........thanks

Customer: replied 9 months ago.
No. Tan Blu. This wire has 4.6v should be B+. Looking for advice for issues here. It's hard to type out
Expert:  Don 'Mo Lurch' replied 9 months ago.

sorry for the misunderstanding, but let me repeat........Fuse 12 powers the Door Module & from there powers the TAN / BLUE, which is the "Main Voltage + wire to operate the Windows, Locks & Mirrors from the Door Module
There is NO "low reference" wire, as the components are powered via 11.8 - 13 Volts DC

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Customer: replied 9 months ago.
Do you have access to a commodity layout? Fuse 12 is good. I need to find the resistance between fuse 12 and door module (master switch away)
Customer: replied 9 months ago.
Auto correct was assembly not away. Darn technology
Expert:  Don 'Mo Lurch' replied 9 months ago.

I need to find the resistance between fuse 12 and door module
???

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Resistance?.......you either have at least 11.8 Volts or you don't at the Door Module or Door Switch TAN / BLUE wire.,
IF you don't, you would "back probe the TAN / BLUE wire to the Fuse Panel "Fuse 12", to locate the issue.
Jeep is not very good on diagrams & Fuse 12 only powers the Door Module, Windows, Locks & Mirrors

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Expert:  Don 'Mo Lurch' replied 9 months ago.

did you need more info?

Expert:  Don 'Mo Lurch' replied 9 months ago.

did you need more information?
please respond or rate my answer

thank you

Expert:  Don 'Mo Lurch' replied 9 months ago.

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clearly there still must be a problem
You have read my answer & not responded

please respond so I can help further, or at least let me know what you found
Rating answer is what was agreed on
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