Electrical tach issue on Aston Martin DB5

[busybrit]

I'm hoping someone can help me with my electrical gremlin.

I'm working on a 1965 DB5 and both the fuel gauge and the rev counter work fine, but the flashers and handbrake warning light do not.


When I move the flasher arm to the on position, "up or down," or pull up on the handbrake, the rev counter drops to zero and the fuel gauge to fall to empty.


When I take off the handbrake or put the flasher arm in the middle "off" position both the rev counter and fuel gauge do not come back on.


However, if I turn off the ignition, then restart the car, both the fuel gauge and the rev counter now work,,, until I move the flasher arm or handbrake!


Any ideas????

 

[DrEntropy]

Sounds to me as if you have a grounding issue someplace in the flasher or handbrake warning lamp circuits (if it HAS a handbrake warning lamp!). My experience with David Brown's cars is limited to a DB2/4 drophead, so well before the example you're dealing with.

 

[busybrit]

Problem solved, thought I'd let you know what it was. The flashers, handbrake warning light, fuel gauge and tach, all on the same circuit.

When the flashers or the handbrake warning light was activated the bulb/s called for more amps than the circuit was able to supply due to having a loose connection. The power draw resulted in sharing the reduced amps that was available, thus shutting down the whole circuit.

Thx Johnb