Brake light mystery

[old-git]

Had a stange problem the other day.

Brake lamp failed on the Chevy Blazer. Dug out a spare one from my store and fitted it. Works fine. However, strange things started to happen. With the engine off pressing the brake pedal resulted in the warning beeper going off.

With the engine running the beeper didn't sound but the dash board lights went out whenever I pressed the brake pedal. At night the dash lights stayed on. Changed the lamp and problem disappeared.

I guess there must have been some sort of voltage leak/short within the lamp that confused the car's brain but was not enough to blow the lamp.

 

[obi_waynne]

My friend had this exact same thing. Perhaps there has been a batch of bad bulbs. His bulb had a contact between the two filaments which caused a short. It lit up his dashboard warning lights.

Have you had a look at the bulb? It should be fairly obvious if it is defective.

 

[HDi fun]

My friend had this exact same thing. Perhaps there has been a batch of bad bulbs. His bulb had a contact between the two filaments which caused a short. It lit up his dashboard warning lights.

Have you had a look at the bulb? It should be fairly obvious if it is defective.

The two filaments are via the -ve (Assuming -ve earth, which just about every car is now). If the -ve 'ends' of the filaments are not connected to the car then all sorts of strange things wil happen when either sidelights or brake lights are switched on.

 

[old-git]

The lamp looked fine, could see nothing wrong with it. Both the brake and side filiments lit up when required, it just confused the beeper and dash lamps

 

[Country Bumpkin]

One of the GTO's we had in had an unusual fault. It would start and drive o.k. but you couldn't turn it off, take the key out and it still ran. Using the indicator with the car turned off and key out would stop the engine!
We traced the fault to a loom between the inside fuse box and the main engine bay harness, a mouse had eaten it !
we have actually had three or four GTO's that have had wiring rectifications by mr mouse and various family members. One GTO came in with A.B.S. faults, mr mouse had eaten through the rear sensor harness, only £350 each !:blink:

 

[HDi fun]

The lamp looked fine, could see nothing wrong with it. Both the brake and side filiments lit up when required, it just confused the beeper and dash lamps

Stick a dvom on it and measure the resistance of each circuit.

 

[old-git]

Stick a dvom on it and measure the resistance of each circuit.

As soon as changing the lamp solved the problem I binned the defective one.