William Keiter
Newbie
I have been working to troubleshoot a rapid flash/no brake light problem on the right/passenger rear light since recently buying my truck.
Checked and changed all fuses, no sign of anything.
The previous owner mentioned he thought it was wiring and I could see a relay hanging from under the dash. This weekend I swapped the taillights and the right rear assembly/circuit board worked correctly when installed on the driver's side rear connector. The problem was still there when using the known good left rear light assembly on the right rear. This should have eliminated a circuit board or bulb issue, replaced the brake bulb on right side just because (no difference).
I then cleaned the rear ground down to bare metal on the frame with a wire brush and steel wool. No luck
Following that I shot the wires for continuity from the rear disconnect to the tail light assembly connectors (all had correct continuity and good ground connection).
I then began shooting for 12 VDC at the rear disconnect and found that I had 12 VDC going to the driver's rear tail light (Yellowish green wire) but 0 VDC going to the Passenger rear tail light (darker Green wire). I went up to the fire wall and pulled back some insulation on the wire and it was still 0 VDC.
After much frustration not finding anything else under dash aside from what appeared to be a piece of cardboard added with tape between the brake switch and brake lever (I removed), I reinstalled everything and went for a drive. During the drive I had the right turn signal go from rapid flash to slow flash! Hopped out and sure enough it was working.
It was intermitent the rest of the drive and I could get it to work by jiggling the pedal with my foot. Appears to be the brake switch assembly. Ordered and should be here tomorrow.
Let me know if I missed anything.
Checked and changed all fuses, no sign of anything.
The previous owner mentioned he thought it was wiring and I could see a relay hanging from under the dash. This weekend I swapped the taillights and the right rear assembly/circuit board worked correctly when installed on the driver's side rear connector. The problem was still there when using the known good left rear light assembly on the right rear. This should have eliminated a circuit board or bulb issue, replaced the brake bulb on right side just because (no difference).
I then cleaned the rear ground down to bare metal on the frame with a wire brush and steel wool. No luck
Following that I shot the wires for continuity from the rear disconnect to the tail light assembly connectors (all had correct continuity and good ground connection).
I then began shooting for 12 VDC at the rear disconnect and found that I had 12 VDC going to the driver's rear tail light (Yellowish green wire) but 0 VDC going to the Passenger rear tail light (darker Green wire). I went up to the fire wall and pulled back some insulation on the wire and it was still 0 VDC.
After much frustration not finding anything else under dash aside from what appeared to be a piece of cardboard added with tape between the brake switch and brake lever (I removed), I reinstalled everything and went for a drive. During the drive I had the right turn signal go from rapid flash to slow flash! Hopped out and sure enough it was working.
It was intermitent the rest of the drive and I could get it to work by jiggling the pedal with my foot. Appears to be the brake switch assembly. Ordered and should be here tomorrow.
Let me know if I missed anything.
