[Gussyb]

I have recently fixed the brake lights on my Suzuki Sierra and one side is working fine getting 12 volts but the other side is only getting 0.5 volts. what is wrong with this and how can I fix it.
Thanks
Gus

[fordem]

What is your experience with electrical troubleshooting & diagnosis? Where and how are you measuring that voltage? Both brake lights are supplied by the same feed so for one to get 12V and the other less than 12V can only be a bad connection or a broken wire. You'll need to check both the supply wire & the ground wire.

[Gussyb]

Iv'e have a fair bit of experience with Landcruiser electrical problems. I have been measuring from the inside of the light housing using a voltmeter and grounding it to the chassis.

[Gwagensteve]

Chassis is basically not grounded on a Sierra. There is one tiny wire that runs from the rear cluster on the passenger side from memory to the chassis, that's it.

[Gussyb]

Ok thanks i'll try that out

[Gwagensteve]

Take your ground measurement from the globe socket, not the body (or chassis) because it's not out of the question the problem is a poor ground on loom. Measuring between the +ve and the body will only prove the light has power, not whether there's a complete circuit.

[Gussyb]

thanks for the tip