Dash Lights flicker when headlights on.

There was a TSB out on applying dielectric grease to the headlamp switch connector for this problem, sometimes it fixed the problem the other times the headlamd switch was the cause. If I were you, I would replace the headlamp switch

Glenn beasley Chrysler Tech

Glenn's right. Over on the 300M Club

LHS - 300M - essentially the same car), this is commonly referred to as the "light show" problem - lots of threads and posts on it - it's been beat to death. I would add to what Glenn said by saying that you can usually (but not always) stop the light show by simply moving the instrument panel dimmer knob to a different position. Also, try turning the knob thru its range of motion back and forth several times (it's a potentiometer - the success of that depends on if the problem is dirt or corrosion on the element and wiper that can be wiped off or if the wiper is not making good contact with the resistance element due to wear or heat damage). Last resort: change switch.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Thanks guys. I'll try out your suggestions and if necessary I'll get a new switch. Glenn Roy

No idea, but I have same symptoms on a 1998 Dodge Grand Caravan Sport dash lights/radio.

Hi...

Taking a big chance here. (Catch me, Bill :)

If by radio you mean the radio display (sound is good, and not "flickering") then the only possible component failure that could cause this problem is the light switch itself, and/or the connections to the switch.

Take care.

Ken

No, by this I mean dash lights flicker and radio sound dies out intermittently too.

No, by this I mean dash lights flicker and radio sound dies out intermittently too.

OK - that's a different ball game. Sounds like you may be experiencing a main power or ground connection problem somewhere (or protection circuits that may be common to dash lights and audio). Do your headlights flicker too?

This is now more of a troubleshooting problem - meaning all symptoms (such as are the headlights flickering too) and tracing power and grounds with schematic and multi(volt)meter.

If your headlightas also flicker, that could narrow it to the main power or ground, but if they are not flickering, then it is more likely a common branch (fused) circuit.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Includes headlights; I was guessing voltage regulation, but maybe not.

Will check the feeds and grounds.

Thanks, and Happy New Year.

Followup: I just looked at the schematics for your LHS. There is no fused branch that is common to the audio system and your dash lights.

Unless I'm missing something, it has to be a main power or ground - and I bet if you pay attention at night, you will notice that your headlights are also flickering. If that's the case, main things to check are: Both connections at battery; positive jump post (all power except the hot wire to the alternator go thru that junction); Main ground - AKA negative jump post on the passenger side strut tower (one stud/nut).

If you find that your headlights are not flickering, then I will at that point be officially confused - unless you have other pertinent info. to add.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

That was a very important piece of information that you have left out.

OK - listen very carefully - lest you think I am casually making guesses as to the cause of your problem, I speak as the owner of two Concordes that are the same car electrically. I have experienced and solved the

*exact* problem. I have seen the same problem reported on the LH car-specific forums - and the almost always turns out to be one of the following: (1) A corroded/loose connection at the battery (2) A loose connection at the positive jump post (3) A loose ground (AKA negative jump post on passenger side strut tower).

Most likely it is (2). That junction carries *ALL* power for the vehicle with the exception of the hot wire to the alternator. It is a stud with three cables clamped on a stud - one cable from the battery, one cable to the starter, one cable to *EVERYTHING* else (lights, dash, radio, etc.). A loose nut on that stud means poor clamping (high resistance, large voltage drop, lots of heat) of the cable terminals to each other. Symptoms can be ecxactly what you have reported, or starter intermittently not working, or the two occurring randomly as the quality of the connection among the three cables changes with temperature, vibration, phase of the moon...

Be aware that the nuts on the stud may *seem* tight, but if they have been loose for a while, the threads can get heated, galled, and lightly welded to the stud, and *appear* tight when actually they are loose (i.e., not clamping the cable terminals, but the nuts don't turn because the threads are arced together from heat and electrical arcing). To be sure they are actually tight (i.e., actually clamping the terminals and not just binding threads), back one of the nuts off (either one - to break the threads loose), and then *re-tighten* with torque on the high end of reasonable.

NOTE: Careful when wrenching the nuts on the positive jump post stud - if your wrench touches any surrounding metal (ground) while it is on those nuts (direct connection to battery +12V), you will have lots of sparks, and possible damage or injury - it would be best to disconnect the ground post while working on that.

But also check (1) and (3) as they have been known to be the cause of the same problem.

You're welcome - same to you.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Appears to have been (1), although I wonder why all of a sudden, other than a quick temperature swing. Will continue to check the other 2 psbl causes.

Thanks again.

Hi...

My turn to add to your thoughts, Bill :)

Disconnect completely the battery negative, then and only then work on the positive post and mid-point connections. Put the battery negative back as the last step in your repairs, and voila! Virtually zero risk of a slipped wrench or dropped tool or piece of jewelery shorting anything.

And I'd not only check for tightness, I'd suggest taking 'em apart, then polishing things up with a wire brush or piece of sandpaper until they're nice and shiny.

Finally, I'd do it now, before it really starts to cost you. If the voltage is varying enough that you can see it in the headlights, it won't be long before you're replacing light bulbs, the radio, the computers, and whatever else that really doesn't like the rapid on/off sequencing.

My usual disclaimer; not a mechanic, just an old retired electrical guy.

Take care.

Ken

Good advice. However, disconnecting the negative ground point (passenger side jump post) effectively accomplishes that without having to access the buried battery (PITA). (Couldn't let you one-up me!! Just kidding - neither one of us looks at it that way.)

Good point.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')