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Amedee
Amedee, Dodge Technician
Category: Dodge
Satisfied Customers: 24415
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
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I have a 2002 ram 1500. When ignition is on brake lights

Customer Question

I have a 2002 ram 1500. When ignition is on brake lights stay on except third cab light. All other lights work properly.When ignition is off all lights work properly. After driving a mile or so the ABS and park brake lights come on on dash. I replaced
brake light switch no change. I disconnected multi function switch no change. Replace ignition switch no change. I replaced heater core a few weeks ago so I went over all the wires and connections found nothing.
Submitted: 1 year ago.
Category: Dodge
Expert:  Amedee replied 1 year ago.

Hello and welcome! My name is ***** ***** I can assist you with your question. When did this brake light issue start to happen? Was it after the heater core replacement?

Expert:  Amedee replied 1 year ago.

Would it be possible to get your VIN?

Customer: replied 1 year ago.
It started several weeks after the heater core replacement. The Vin is 1B7HU18NO2J103400
Expert:  Amedee replied 1 year ago.

Thank you for that information. One minute while I pull up your vehicle.

Expert:  Amedee replied 1 year ago.

Ok, this problem is caused by a bad integrated power distribution module, CHMSL (even though it is working) or a bad left/right tail lamp assembly. Basically, you will need to run some tests in order to see which component has gone bad. Let me explain...

Expert:  Amedee replied 1 year ago.

The CHMSL needs to be working with the proper bulb for the instrument cluster to see the correct input from the brake switch.

Expert:  Amedee replied 1 year ago.

You could disconnect the tail lamp assemblies and check to see if the brake light circuits are not working/getting power (using a test light or a voltmeter). If so, then one of the tail lamp assemblies is bad causing this condition.

Expert:  Amedee replied 1 year ago.

By checking/replacing the CHMSL and then verifying that the brake light circuits going to the tail light bulbs are not working correctly, then I would suspect a bad integrated power distribution module under the hood.

Expert:  Amedee replied 1 year ago.

That would be a last resort. I have a feeling you will find something sooner (and much more simpler) once you run these tests I have provided.

Customer: replied 1 year ago.
Where is the CHMSL
Expert:  Amedee replied 1 year ago.

That is the Center High Mounted Stop Lamp

Expert:  Amedee replied 1 year ago.

I am glad I can help! Please dont forget to honor your good faith deposit by rating my answer as "Excellent Service" for assisting you today.

Expert:  Amedee replied 1 year ago.

It has been a pleasure! Please let me know if you have any further questions!

Customer: replied 1 year ago.
The CHMSL is working properly with ignition on and off
Expert:  Amedee replied 1 year ago.

Right, I understand.

Expert:  Amedee replied 1 year ago.

I am just telling you how the system works. It is possible that even if the CHMSL is working ok, this can still affect the other brake lights.

Customer: replied 1 year ago.
What is involved in replacing the integrated power module. Does it need to be done by a pro?
Expert:  Amedee replied 1 year ago.

It is not hard to remove and replace. However, it may need to be configured using a factory scan tool once it is installed. So you can replace it (if needed) and then have someone configure it.. or just have the dealership install it and configure it once it is installed. Either way, as long as it is installed and configured correctly..

Customer: replied 1 year ago.
OK thanks
Expert:  Amedee replied 1 year ago.

You are most welcome!

Expert:  Amedee replied 1 year ago.

I am glad I can help! Please dont forget to honor your good faith deposit by rating my answer as "Excellent Service" for assisting you today

Expert:  Amedee replied 1 year ago.

It has been a pleasure working with you. You should see the rating system towards the bottom of the page.

Expert:  Amedee replied 1 year ago.

You should see the rating system towards the bottom of the page.

Customer: replied 1 year ago.
It appears the the problem is not the tail lights. When you say the integrated power distribution module do you mean the front control module or the integrated power module ?
Expert:  Amedee replied 1 year ago.

Hello and sorry for the delay! I could be either. However, I was talking about the intagrated power module. You might want to replace both of them at the same time just to be on the safe side.

Expert:  Amedee replied 1 year ago.

Hello!

It's Amedee from just answer. I am just checking in to see how things turned out and if you need further assistance. Please let me know.

Amedee

Customer: replied 1 year ago.
I'm waiting for the fuse box and FCM. Hopefully they'll fix the problem
Expert:  Amedee replied 1 year ago.

Sounds good! Thanks for the heads up!

Customer: replied 1 year ago.
I finally replaced the fuse box and control module but it didn't fix the problem. I can't figure why the ignition would cause the computer to think the brakes are applied and turn on the brake lights and disengage the cruise control.
Expert:  Amedee replied 1 year ago.

Hello! Can you send me your VIN so I can do some digging for you?

Customer: replied 1 year ago.
1B7HU18NO2J103400
Expert:  Amedee replied 1 year ago.

Hello and sorry for the delay! Thank you for sending the VIN (again). Lets run this test.

Remove the fuse for the brake lights from the Integrated Power Module. Use a jumper wire to ground the White/Tan wire at the brake switch. If the rear brake lights go out, repair the Center High Mounted Stop Light (CHMSL).

Expert:  Amedee replied 1 year ago.

Here is a wiring diagram.

Customer: replied 1 year ago.
I did the test and there was no change. I guess I'll have to get over my stubbornness and admit defeat.
Expert:  Amedee replied 1 year ago.

Hello and sorry for the delay! Can you tell me how you did the test and what were the results?

Customer: replied 1 year ago.
I pulled the #15 fuse and grounded the white/tan wire at the brake switch with ignition turned on. The brake lights remained on.
Expert:  Amedee replied 1 year ago.

Hello and sorry for the delay! Did you do this with the connector connected or disconnected from the brake switch? Because this will make a difference.

Customer: replied 1 year ago.
I left it connected to the brake. I'm away for work this week and next so I won't be able to do any more work on the truck.