`29 La Salle Electrical System Knowledge

[NH LaSalle]

I have an issue with the electrical system my `29 La Salle 8550 sedan that I am restoring; one that I've been yet to solve.

Essentially, with the new wiring done, all of the electrical components on the car work EXCEPT the horn and the brake lamp.

If I disconnect the horn wire from the  firewall's terminal block and run a jumper wire from the battery directly to it, the horn works.  Similarly, if I remove the brake light wire from the terminal and attach the jumper wire to it, the brake light works.  However, once they are back in tandem position on the terminal block, they don't function.

The horn feed and the brake lamp feed both attach to the same post on the terminal block; the same post that receives the power from the lock-out circuit breaker (and both are literally touching the incoming power source) and because all other components that derive their power from the terminal block, I don't suspect that there is a short in the block.  Also, all other components that are on the same lock-out circuit as the horn and brake lamp work.

The 'switch' at the bottom of the steering column is new.  The fact that the horn works with a direct attachment to the battery makes me think that there is not a short in the horn terminals in the 'switch'.  And the brake light does not go through that switch.

There is a full charge on a new battery.

Any thoughts/approaches to solving this perplexing issue appreciated.

[J. Gomez]

I have an issue with the electrical system my `29 La Salle 8550 sedan that I am restoring; one that I've been yet to solve.

Essentially, with the new wiring done, all of the electrical components on the car work EXCEPT the horn and the brake lamp.

If I disconnect the horn wire from the  firewall's terminal block and run a jumper wire from the battery directly to it, the horn works.  Similarly, if I remove the brake light wire from the terminal and attach the jumper wire to it, the brake light works.  However, once they are back in tandem position on the terminal block, they don't function.

The horn feed and the brake lamp feed both attach to the same post on the terminal block; the same post that receives the power from the lock-out circuit breaker (and both are literally touching the incoming power source) and because all other components that derive their power from the terminal block, I don't suspect that there is a short in the block.  Also, all other components that are on the same lock-out circuit as the horn and brake lamp work.

The 'switch' at the bottom of the steering column is new.  The fact that the horn works with a direct attachment to the battery makes me think that there is not a short in the horn terminals in the 'switch'.  And the brake light does not go through that switch.

There is a full charge on a new battery.

Any thoughts/approaches to solving this perplexing issue appreciated.

If I may suggest to start checking that power is available at the terminal block from the CB lockout with the ignition switch in the off position.

The brake lights and horn would require a direct power feed while the others on that terminal may be feed from the ignition switch when is on.

HTH

Good luck..!