signal light

[quack]

while my signal light is on and i press the brake it goes very fast when i release the pedal its normal again is it a new option from gm if not anybody know the problem


Thank You

[1999montana]

Originally Posted by quack

...while my signal light is on and i press the brake it goes very fast when i release the pedal its normal again is it a new option from gm if not anybody know the problem....

Could be a bad flasher, but also a bad ground (front corner signal or rear turn lights.)

Or it may be time to replace the entire connector board in the taillight assembly(s).

You could start by checking for a bad ground.

Electricity is funny, it will find a path to ground just as water will find its own level. If the 'normal' path to ground is not available, it will feed back through any available circuit close by.

To check, you can have someone operate the lights, signals and brake lights while you walk around the vehicle doing a test at each corner. Cycle through a complete test of lights, signals and brake lights at each corner. Watch for anything that looks odd; - like lights that should be on go out or glow very dimly, that would indicate a bad ground.

Trace the ground back to where it connects to the body checking for continuity as you move closer to the ground point. Wouldn't hurt to have a schematic that shows the connections and ground references.

Also pay close attention to the rear bulbs, particularly the snap out connector that pops out of the tailight housing.

You need a torx screw driver to remove the taillight housing(s) from the rear of the van (two screws in each housing).

Once removed, disconnect the harness then remove the entire assembly.

What you are looking for are bulbs that have literally melted into the connector board.

Could be that one or more are shorting out between parking lights and the brake/signal lights.

Just a guess. Hope this helps.

[soaper]

i had this same problem. replaced the signal bulb and the issue went away!

[LMP]

My brother with exactly same car...and a lot of others...had serious corrosion problem in the two tail light clusters. Remove and check.

[jvh003]

I had exactly the same problem with my 99 montana.
The driver side signal would flash quickly only while applying brake, without brake it was normal.
Other intermittant side effects included:
- both left & right signal dash indicators would light up at same time while braking, while signal not activated
- ABS & TCS lights would intermittantly come on, sometimes triggered by putting van in reverse, or originally triggered by touching brakes to disengage cruse control on hiway

Scouring thru this forum, I tried the following:
- check brake fluid (was ok)
- check all signal blubs with ohm meter (all ok)
- check ABS connectors on front wheels (after this... ABS/TCS light would almost engage every time I put the van in reverse... seemed to be a red-herring).
- check both rear signal assemblies, including taking a part the plastic bulb holders to get access to the internal circuit boards

Ah Ha.... there was a problem in the driver side 6 pin (5 wire used) female connector to the bulb holder. The ground pin (black wire) connector was melted! This caused a grounding problem !
So... I cleaned it out to regain a good connection, but also ran another ground wire from the ground spine on the circuit board to a body ground screw inside the cabin.

So far so good.... been driving 3 days now with no more signal issues or any of the other intermittant problems.

Thanks for all the help.... this fourm is an excellant source of info !!

Anyone know if there is a GM recall for this problem ?
Seems like there should be, since turn signals relate to safety.