L200 dash lights blink when the headlights are on
 

I need some help! I have a 2002 L200, when I turn my headlights on (manually or auto) the dashlights blink, security light comes on, headlights blink (unless I manually turn them on), the gas and temp gauges jump and the odometer quits working. I have read that LED headlights could cause this issue so I changed back to conventional bulbs, same issue. Also read the dimmer rheostat could cause this, mine has not worked for years so I took it apart and made sure no broken contacts moved that could cause shorting, no change. I have checked all the fuses that have to do with the lights to see if something crazy was going on with them, all looked good. Pulled the headlight relay replaced with another relay, same thing. I have found that if the daytime running lights or Highbeams are on, I don't have this issue. Any other suggestions beside a new BCM?

Andy should be along shortly. Resident L Series expert.

Do you have the correct multi-function switch installed? There is no off position on a 2002 L series switch. I bought a 2002 that had light problems and it had a switch for a 2000 installed. I installed the correct switch and solved the problems. I have a 2000 LS1 and there is an off position on the switch.

https://cimg5.ibsrv.net/gimg/www.sat...8ed5c931d2.jpg

That is the same switch I have. If I turn my lights to the "on" position, the headlights don't flash, however if I leave them in the "Auto" position, they flash and people think I'm warning them of somethnig! They don't flash in either position if the High Beams are on.

My headlights wink one time when I lift off the throttle. If they do it many times I cycle the ignition switch to start a couple times while driving and they quit winking. I suspect that I may need to replace my ignition switch. You have many more symptoms of a bad bcm since it controls the dash and probably the automatic functions of the headlights. If you have access to an advanced scanner check for body codes, that might help diagnose your issues. I do have a factory set of manuals for a 2002 L series.

The more I thought about what you said on the multifunction light switch, I replaced it in hopes that was the issue. No such luck! I took it to a shop to have the body codes read, they didn't tell me wha tthe code were but it is looking more and more like the BCM. The shop believes it was my LED lights that caused the problem, however, I have had the lights in the car for over two years and this issue just started. Is that possible?

Should it come down to replacing the BCM, can they be fixed or do they need to be replaced? The shop told me they have had them repaired in the past for about half the cost of a new one.

Thanks for all your help.

There is no logic to the LEDs causing the problem. I would be wary of that shop.

Cover the sensor in the center of the dash and the lights should turn on after a slight delay. Drive it this way for a few days and see if any of the other issues occur. It is a solar load sensor for the a/c with automatic air and the lighting control for the auto headlights. The lights will turn on and off with the key so this is a valid test. If you now have zero problems I would replace the sensor before dealing with a BCM.
Andy

Zillions of Saturn owners have successfully installed LED lights following the proper procedures.

Since you paid for the diagnosis, I would push them for the diagnosis codes. Seems fair to me. They should not be averse to you taking the diagnosis and going home and fixing it yourself. They've made their money.

Unfortunately some shops withhold such information and provide vague pseudo explanations and worst case scenarios so that they may frighten you or convince you that the problem is something far more expensive to fix.

In this case, I'm going to guess that Andy is correct. The mechanic probably knows this and after changing your BCM and charging you up the wazoo, he will also say and by the way your dash thermal load sensor was bad, thinking you won't give that a second thought.

Food for thought. Run away. With the codes.