Brake Light Control Board

[bigsky]

Having lots of trouble with intermittent brake lights. Cleaned the bulb holders, and the harness contacts. The lights will come on and off depending on how, or where the contol board is moved, or flexed. Bad ground? Bad board? What is a fix?

[jawn101]

The boards are known to go bad as they depend on brass rivets to make connection to the solder traces. There are several ways to fix this, including replacement of the boards (either with NOS or upgraded PJ Grady ones), having the boards refurbished (Hervey at Special T does this for a very nominal fee), or you can try using a wire brush carefully on the rivets and then knocking them with a center punch to expand them and hopefully improve their contact. I don't think that last option is for the faint of heart as the boards are fragile enough as it is.

Personally I had my boards refurbished by Hervey and they are brighter than before and much more reliable.

[DniveK]

Clean the contacts on the plug and on the board. Also solder the connections on each of the bulb holders. Those boards are weak in every way, invest in new stronger built boards from Grady.

[sdg3205]

If you want, before investing in new boards, try the nut and bolt fix. It's about $2 so if it doesnt work, you can spring for the new boards.

Basically, you just get some small nuts and bolts (drill the holes SLIGHTLY larger if needed) and insert the nut and bolt. Tighten well. Problems gone.

Perhaps someone can chime in with the sizes. I forget. M2?

[bigsky]

You are referring to drilling and putting bolts and nuts through the rivets to improve the ground connection?

[sdg3205]

You are referring to drilling and putting bolts and nuts through the rivets to improve the ground connection?

Roger.

I just took the boards to home depot to find which ones would work.

[bigsky]

Roger.

I just took the boards to home depot to find which ones would work.

Got it, gives me something to do this week!

[DMCMW Dave]

Here's an oldie but goodie:

http://dmcnews.com/Techsection/tailights.htm

They are #2-56 screws. Still showing "live" at Radio Shack.

[bigsky]

Thanks everyone for your help, I also noticed the drivers side lens, the backside where the bulbs enter was melted in several spots. It melted around the bulbs, and had to be reworked. I appeared the exhaust had caused this at one time. Anyone ever run into this?

[jawn101]

Thanks everyone for your help, I also noticed the drivers side lens, the backside where the bulbs enter was melted in several spots. It melted around the bulbs, and had to be reworked. I appeared the exhaust had caused this at one time. Anyone ever run into this?

It would be weird IMO for the exhaust to damage the taillight lens and not the fascia. On the drivers side it could have been the cat I guess, if it was running really rich and got red hot... but you'd see warping or damage elsewhere too. It would most likely be the bulbs, but I'm not sure if they can get hot enough to melt those taillight assemblies.

[Michael]

My logic on this issue (as I had the same problem on my refurb.), was to replace the light boards with the PJ Grady boards. The reason behind this was liability. I didn't want to have my car rear ended, and be my fault on top of that....also I don't cringe and everytime I'm stopped watching someone approaching from the rear wondering if my light board fix is still working.

There are some Delorean things that one can justify saving a little coin on, and some that should be fixed 110%...brake lights fall in the latter.

[jfirios]

I am having problems with my break lights too, I think I have asked about it before, most people say it sounds like a short but I have one origional board and one new one from Grady, that the PO left in the car for me. But when I depress the break peddal, the lights dont come on immediately, they slowly dim up. That is what has me scratching my head and it happens both on the new board and the old one. I would love to have them work propperly but not shure where there could be a short or if it is a short at all. any ideas

[aludden]

[...]
when I depress the break peddal, the lights dont come on immediately, they slowly dim up.

Time for LEDs? ;-)
When I put mine, I did one side first to compare, and the LEDs came on instantly, the bulbs didn't -you kind of see them warming up. It's not that noticeable when you just have bulbs, but side by side it's very obvious.

Anyway, I would test the ground by running a ground wire straight from the battery and clip to the board - see if that makes any difference. And also try attaching that ground wire to the bulb socket itself.

[jfirios]

oh i would love to put led's in there. and it is a very noticiable warming up of the bulbs. they dont come right on like a normal cars rear lights should. Your saying just take a length of wire attatch to the ground of the battery and then to the board while it is all connected and then try it?

[aludden]

oh i would love to put led's in there. and it is a very noticiable warming up of the bulbs. they dont come right on like a normal cars rear lights should. Your saying just take a length of wire attatch to the ground of the battery and then to the board while it is all connected and then try it?

Yes, to the ground terminal of the board if possible, or someplace where you have a good contact with the board's ground. This would rule out any possible ground problems. If it works OK, then your ground going to the board is probably corroded. If it's not OK, then try it at the base (ground) of the bulb itself. If that works, then you may have a problem with the board itself. And if that doesn't work, then the problem is not with the ground, but with the hot side instead. Does that make sense?

[sean]

Any idea how old the bulbs are?

[jfirios]

the bulbs are brand new, that was the first thing I thought of.