QuestionQUESTION: 2002 T&C LXi, 3.8L FWD. Problem: over the last 6 months the control backlights on lower instrument panel fail one by one. Half still light, but 1-2 more go out each month it seems
Ex: PWR, Recirc, front blower switch, and defrost positions on cabin air control switch are all "dark". Also, the passenger heated seat switch (upper instrument panel)does not light up (the heat works). Rear system selector switch and labels all work. All controls work; some of them are just not illuminated.
All cluster lights/gauges are fine. Disconnected battery to reset PCM, BCM. There are no trouble codes. Q: aren't the backlights individual LED's? How do I open case for lower instrument panel to troubleshoot/replace LED's? Source for new LED's? Thank you for your help.
ANSWER: Hi Alan,
This will take a bit of research. Can you verify that PWR stands for heater/ac power? Are all those illuminations that have failed dimmable? Do you have manual temp control or the automatic temp control? Are all the non-working lights associated with heater/ac controls, except of course for the heated seat?
Thanks for clarifications.
Roland
---------- FOLLOW-UP ----------
2002 T&C lower instrum
QUESTION: Roland,
Re: 2002 T&C LXi, 3.8L with individually failing control backlights
The lower instrument panel (below the radio. This is the name Alldata uses) is entirely heater/AC controls. It is self-contained and measures 8.5x3.5x2.5d
There are two connectors in the back from the harness. The heat-A/C in this vehicle is 3-zone auto temp.
In this Lower Instrument Panel the top center area is a green digital display with temp readouts for Driver, Rear, and Pass zones.
I can send a photo(s) if it would help.
To the far left of the unit, there is a push on-off switch "PWR" that powers the entire lower panel. Between the PWR and temp display, there is a vertical
rocker switch: Hi-Auto-Low. To the right of the display there is a "snowflake" switch for A/C, a recirc switch, and a defrost switch. The unit has auto temp control.
Except for the pass heated seat switch light, all non-working lights are in the lower instrument panel. However, some of these lights work; others do not. All
working lights are dimmable as are the cluster lights. All non-working lights used to be dimmable as well.
There are three round, rotary switches beneath the display area. Left switch is "Front" and is the front blower speed control. The middle switch controls the rear system, and the right switch is a 5-position rotary switch that controls air flow.
There are detent indicator lights for all three controls. These detent lights all work. The lights that are failing are all icon backlights or label (text) backlights.
Since some work and some do not, this doesn't appear to be a power bus problem. Probably not a bcm problem either. The failed heated-seat light in the upper instrument panel would suggest that the problem is the individual light sources.
I have found very little info on the internet on this except that the backlights seem to be individual LED's soldered to a circuit board in each instrument panel.
I used to work in electronics years ago, so I am willing to replace the LED's if they are the problem. Question: how do I open the lower instrument panel case? It is a self-contained unit. I don't want to damage the unit trying to open it. And do you have a source for the LED's?
BTW, I could not find a "thank and rate tab" to use for followup. Also, your profile is configured not to accept ratings. I'm waiting until you are back online
to send this. Thanks again for all that you do.
Alan
AnswerHi Alan,
Thanks very much for the complete description of the situation. I checked the 2002 shop manual I recently acquired and find there are no instructions for opening up the control unit. The circuit diagrams do show the bulbs are all LED's which derive their power from the control unit itself, individually, with no indication of the voltage at full brightness. That you should be able to measure. Ideally an electronics supply house may have a replacement bulb for you. I would appreciate knowing which one it is so I can note it for future reference. I will also keep track of your very fine description. I wish that I could be more helpful to you but internals of the various modules are not covered by the manual so you pretty much have to work it through using your experience in matters electronic.
Roland
PS On the 'thank/rate', I decided to temporarily drop that option with the new year when I discovered that the site management was not exercising enough oversite of the recognition facet of the process (top expert of the month competition did not identify various techniques for self-aggrandizement such as asking self-questions, no limit on the number of questions one person (presumable a friend) could ask, seeking 'nominations' from very stale questions (over a year old), etc). I did this to protest the situation and to encourage them to make the necessary changes. To see such games being played soured me on the whole idea. If they deal with these problems I will opt back in for sure. It is convenient to use it for quick follow-ups and so I miss that aspect, but I am hoping they will complete the revision shortly.
