[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.