Electrical Problems

[Steverado 99]

Hey all,

 

I am having some trouble with my left turn signal that started a couple of days ago.....some history

I recently got a cap for my truck that has a 3rd brake light and a dome light.  The store wired it up wrong to begin with so I got the wiring diagram from the haynes manual and fixed it.  The 3rd brake light in the cap is wired into the left taillamp (they had wired the dome light the first time) and connects to the brake light wire and to the ground wire.  Everything worked fine for a couple of weeks.  

Now when I turn left the signal works fine, but, if I step on the brake the signal stops flashing and remians solid (left side only, front and rear turn indicators) Also if I put my foot on the brake (no signal) the left turn lamps light up and stay solid.  The right side is OK.  The left turn indicator on the dash also lights up when I use the brake (remains solid as well)

Sooooo,

I checked all the bulbs-ok

fuses are ok

I removed the wiring to the cap-problem still remains

I used a volt meter on the turn lamp and found that when I use the brake and turn signal the left side reads a steady 8.5V. The right side (working side) seems to go from 2V up to 6V and then back down in a repeating pattern.  

 

I am stumped considering I didn't touch any of the turn signal wires and everything was ok for the last 2 weeks

 

any ideas?

 

Thanks,

Steve