Gee It's Never Done that Before

I remember as a kid going with my dad to drop off the '68 Ford station wagon to the dealer.

The car had some electrical issue where the turn signal lever would somehow activate the horn and turn on the radio.....lol!

So, I've been getting my '04 RT sorted out and after repairing the right side stick coil harness, activating the left turn signal switch will flash only the rear left bulb.

But in synchronization with the flashes, the tach and speedo backlights go on and off and the fog light and high beam indicator also flash on and off.

That's with just the key on. If I start the engine and hit the L. turn signal button, the engine dies.

Thanks,

RPG

I remember as a kid going with my dad to drop off the '68 Ford station wagon to the dealer.

 

The car had some electrical issue where the turn signal lever would somehow activate the horn and turn on the radio.....lol!

 

So, I've been getting my '04 RT sorted out and after repairing the right side stick coil harness, activating the left turn signal switch will flash only the rear left bulb.

 

But in synchronization with the flashes, the tach and speedo backlights go on and off and the fog light and high beam indicator also flash on and off.

 

That's with just the key on. If I start the engine and hit the L. turn signal button, the engine dies.

 

Thanks,

 

RPG

Morning Rick

Strange one indeed.

I can't say I know what YOUR problem is but in the past I have seen similar in automobiles with a grounding issue. The low side (ground) main ground is open so the effected accessories ground through a bulb or bulbs. When those bulb or bulbs are powered on then the ground becomes high & those accessories quit working,

My first suggestion is to verify that all your grounding connections are tight & resistance free then if nothing found use your voltmeter to run voltage drop tests on all grounding while the effected circuits are under working load.

You might also remove both left side turn signal bulbs then see if the engine will start. (this removes the bulbs grounding from effected circuits)--Or with engine running, remove each (both) bulbs & see if engine quits.

Are you sure that it is using the L/H turn signal that makes engine quit & not just slightly moving the handlebars? (BMW oilheads are known for the wiring running to the ignition switch fracturing near one of the zip tie retaining points)

Is your battery cables & small power wire making good continuous connection to the battery posts?

Check back later as I will think on this problem some more & might have more info later.

First thought here-- See if you can figure out if it is quitting due to a 12V loss or a grounding loss (ie monitor 12v into coils, injectors, Motronic (both 12v full time & 12v ign switch supplied).

Morning D.R.,

thanks for the quick response. I think it's a grounding issue also. In pursuant to my other running issues, I examined the wiring harness under the tank to be certain that all the grounds were tied to together, with voltage drop tests, showing all was in order.

The right side stick coil connection was broke so that was replaced Tuesday evening. Can't say the problem was there before that repair, but I don't believe so.

I will remove both bulbs as suggested. Last night I only had the time to remove the front (non-flashing bulb) and swap it with the right front bulb. Same problem. Only the right side turn signal system works correctly (both bulbs flashing, engine running).

It's definitely not an issue with turning the handlebars as that was ignition harness was repaired some years ago (losing power when turning bars) and re-examined recently with the ignition switch contacts cleaned and lubed. But I only moved the bars very slightly so I'll be more thorough in that testing this evening.

I also removed the turn signal relay which obviously doesn't allow the problem to occur, but I thought it was worth a try.

Damn, and I just got the engine to start and idle normally with the stick coil repair....

No worries. I love electrical challenges!

Thanks for your help as always,

RPG

Morning D.R.,

 

thanks for the quick response. I think it's a grounding issue also. In pursuant to my other running issues, I examined the wiring harness under the tank to be certain that all the grounds were tied to together, with voltage drop tests, showing all was in order.

 

The right side stick coil connection was broke so that was replaced Tuesday evening. Can't say the problem was there before that repair, but I don't believe so.

 

I will remove both bulbs as suggested. Last night I only had the time to remove the front (non-flashing bulb) and swap it with the right front bulb. Same problem. Only the right side turn signal system works correctly (both bulbs flashing, engine running).

 

It's definitely not an issue with turning the handlebars as that was ignition harness was repaired some years ago (losing power when turning bars) and re-examined recently with the ignition switch contacts cleaned and lubed. But I only moved the bars very slightly so I'll be more thorough in that testing this evening.

 

I also removed the turn signal relay which obviously doesn't allow the problem to occur, but I thought it was worth a try.

 

Damn, and I just got the engine to start and idle normally with the stick coil repair....

 

No worries. I love electrical challenges!

 

Thanks for your help as always,

 

RPG

Morning Rick

You have a very rare problem & those are not only be difficult to find & isolate but even more difficult to be SURE that you have the root cause repaired & not just temporarily covering something up.

With what you have been fighting, plus you keep finding new things, I do believe that if it were me that I would buy about a dozen 12v LED's, some 20 gauge wire & about 2 dozen small 150 male terminals.

Then place an LED across the Motronic B+, 12v ign +, & Motronic ground circuits. Also place an LED across a fuel injector, lower plug coil, fuel pump, etc. See what ALL is failing at the same time so you can get a common 12v supply, or common grounding, failure point. Maybe even put LED's on some of the key fuses to verify that they are staying power up when engine quit appears.

You need to find the common failure point then track it from there to it's root failure point. If you monitor enough KEY power & ground points you will eventually uncover the common failure area (or at least close enough to peruse that area in more detail)

Didn't you swap some relays a while back? If so then maybe you moved the problem with the relay swap.

Good morning D.R.,

I didn't get a chance to work on this over the weekend as my wife had some surgery.

Appreciate the advice on the LED's. It's a great idea. I'm going to order those with the terminals, and dig into this ASAP.

Stay tuned, I hope I get to the bottom of it.

RPG

and yes D.R., I did swap the Motronic relay out for a new one. The old was was registering only 9.8-10.4vdc on the GS911. The new one restored the 12.7vdc value.

RPG