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2003 lesebre limited problems lighting

04-21-2018, 01:35 AM
hi 2003 Buick lesabre limited.. i bought the car radio display works buttons do not light up.. Climate control display works buttons don't light up. steering wheel controls also not lighting up..

Things i have tried so far !!
1 checked all fuses under under hood and under backseat..along with 2am three fuses under the steering wheel..

2. replaced twilit switch brand new
3. replaced climate control with brand new one didn't solve the problem.

any one have knowledge of what it is? greatly appreciated.

Blue Bowtie
04-21-2018, 08:33 AM
Check the 7.5A PANEL fuse. If that is intact, there is a junction block connector which passes all interior lighting. A good hint is whether the glove box light is working. It is not on the dimmable part of the circuit. If it is working, check the dimmer control.

04-21-2018, 11:20 AM
Check the 7.5A PANEL fuse. If that is intact, there is a junction block connector? thats in the backseat fuse panel? i dont see a 7.5 fuse any wheres?

Glove box light is working.. i replaced the HEADLIGHT SWITCH DIMMER TWILIGHT.. the new swtich makes all other lighting go from dim to dark.

thanks for your help this problem is driving me crazy rather not take it to dealer probably cost alot ..

Tech II
04-21-2018, 12:52 PM
This is not you basic dimmer circuit......

In the old cars, you would feed a dimmer module and it's output would send power directly to each bulb on the circuit....

Not the case with a 2003 Limited.....we are talking modules here folks.......and these modules communicate via serial data.....

For example, the dimmer switch sends a variable voltage to the IPM.....based on that, the IPM(instrument panel module), sends out a signal via Class II serial data to the Dash Integration Module, which then sends out a variable voltage to the Steering wheel, HVAC, radio lights, etc.......

There is a 10A DIMR fuse that powers these lights....that's about all you can easily check(rear fuse block).....

You need a Tech II scan tool to read "B" and "U" codes to see if they exist.....and if you are good at diagnosing with electrical schematics, first place to start is a schematic of the Dash integration module.....

Possible problems are, no power to DIM, no communication between IPM and DIM, bad DIMR fuse, an open circuit, bad DIM, etc. Like I said, not an easy system to diagnose.....

If determined to fix it on your own, first thing to do is get a schematic of the DIM in the dimming circuit, test light, and DVM......disconnect the harness, and check for voltage in and ground, and also that you are getting serial data into it....

You can also jumper the voltage, in to the DIM, to the output circuit of the DIM(via the disconnected harness) to see if the lights go full bright, just to test that circuit....

04-21-2018, 02:02 PM
Thanks 10a fuse is good.. can u explain what b & u codes would mean if there are any ? is it better to buy scanner or take it to garage?

Tech II
04-21-2018, 02:32 PM
"B" codes are called body codes, and they usually set if there is a module problem...."U" codes are communication codes, and usually are set if there is a communication problem between modules......

Don't waste your time on a scan tool.....cheap scan tools and code readers only can read "P", or power train codes......

Only expensive scan tools like a GM Tech II, or high end Snap On scanners can read these codes....only big garages would have these scanners, if they want to stay in business...

If that fuse is ok, AND is getting power(check with test light), that means the DIM is grounding the park lamp relay, sending power through the fuse to the DIM......so either the DIM is not getting a signal to turn on the lights, the DIM is bad, or there is a circuit problem(an open after the DIM)......

04-28-2018, 11:32 AM
should the steering wheel buttons light up are these back lit?

Tech II
04-28-2018, 03:39 PM

05-05-2018, 09:59 PM
I have the following codes :::

says instrument panel module fault 2 module id 9e53 red calibration id 9E53 Shows in red electronic front end sensor 1 id E1 red component sn bt22 red

rear module prom id 231c in red all other ids are in black..

another thing says prom id red letter and number code

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