Weird Electrical Problem

[da12ask]

2006 PT Cruiser. Intermittent problem. When I turn on the headlights, the dash lights will blink, then stay off. The headlights are on fine, but the dash lights, and the running lights, stay off. Looking closely, when the switch is turned on, you can see the running light bulb flash 5 times and stay off. 5 times, exactly, every time.

Now, to make this even more fun, this is an intermittent issue. Some times, usually when I have time to troubleshoot, I flip on the lights and everything is fine. Can't make it do it. But, on occasion, I'll get the blinks and then the dash and running lights are out.

Battery is fine, charged and charging.

Anyone have any ideas?

Thanks

[oldcoach]

Do you only have the issue when you are driving the PT?
It sounds to me to be a ground issue.

[da12ask]

Nope. Sometimes I come out to start it and they won't light up. Other times, I'll be driving and they go out. Only using it in the daytime because the police seem to take a dim view of driving at night without tailights. :-)

Like I said, real intermitent. What is strange is the 5 blinks when I turn on the lights. Always 5. Has to mean something, but I am at a loss as to what.

What's a good method for troubleshooting a problem ground?

[slartyblarfast]

I have seen this before..... It's been a long time ago and I can't remember what it was..... let me do some research and see what I can come up with. If I remember correctly I had to end up replacing the instrument cluster.....

[da12ask]

Ah HAH!!! Found it! And this has happened on other vehicles before.

The trailer brake controller was faulty. Cut out the controller and everything started to work immediately. Not sure what is wrong with that little black box, but removing it did the trick.

That was driving me nuts! What was truly odd was that I was getting 2.75V on the inoperative backup lights when I turned the light switch on. No idea why, but you have to ask yourself what could be resisting the voltage down, vs just being on or off, and that led to the brake controller. Took a bit to find it, but found it dangling off the left rear tail light wires with some rather slap-dash crimp splices.

So for anyone with weird electrical issues, might want to cut out the trailer wiring before going too far chasing grounds and what-not.

[CREWZIN]

It also helps US to know that extra electrical work has been done to the vehicle. Lots of owners come here just just that sort of problem and we find out latter that a megawatt 10,000 amp stereo system, 15 TV's or a killer security system was added to the PT only to have problems later on.

Aftermarket add-ons are the first thing that should be checked when electrical problem arise to include trailer hitches, remote starters and add-on fog lights.

This is for anyone else having electrical problems.

[da12ask]

Ok. I'll remember that in the future. Appreciate you pointing that out so promptly.

Consider me chastised.

I would like to thank all the others that did try to help. Much appreciated.