Its been a while since I've posted here. I guess the troopers been running so great and a few other projects have consumed my online forum time that I haven't been around much. But when I need to find out somethin' Trooper-wise, I know this is where to look.

So my wife complains that the radio is acting weird. She says that whenever she turns on the left turn signal the lights on the Disc changer start flashing...
After playing with it for a while I discover the following oddities.

You know how when the truck is running and all the dash lights are on bright for daytime and when you turn on the headlight how all the lights are still on but are in dim mode? (this is normal but it sets the stage)

No key in ignition, pushing the brake pedal causes the dash illumination lights (dashboard, radio, Vanity mirror lights) to light up as if the head lights are turned on (dim mode).

Also does this when truck is running (headlights off). Hit the brakes all dash lights go to dim mode.

With the head lights off, when you turn on the left turn signal all the dash lights (radio etc) flash to dim when the turn signal is on and back to bright when it is off (flashing in sync with the turn signal).

No oddities appear when the right turn signal is activated.

When the head lights ARE on, no odd behavior is seen.

All the headlights, stop lights and turn signal are in working order.
To me it seems like a short somewhere. I'm pretty good with mechanical gremlins but could sure use some suggestions on where to start looking. (although a local auto electrical shop is where I might end up looking first....)
Thanks

First, if you have a trailer wiring harness, unplug it. They cause odd things when they go bad. If thats not it check/replace the brake/tail light and turn signal light bulbs. The filiments can break but short out and still seem to be working but cause weird things. Also make sure the bulb holders are clean and in good working order.

Isuzus do weird things electrically when there is a small problem somewhere.

I had this happen on two separate occasions. In one instance, the front turn signal housing had gotten really corroded where the bulb goes and was shorting out. The other time, one of the wires on the back of the front turn signal assembly had broken. The first time it eventually killed my radio before I could track down the problem.