Triumph Repair: Electrical -TR3, jumper cable, tr3b

Question
Hi Jim:

I just acquired a fully restored TR3B. After having the safety inspection completed, along with a new water pump and fuel pump installed, and driving the car for all of 15 minutes before parking in my garage, I now find that it will not generate any electrical power at all when the ignition key is turned.No reaction from the starter motor switch, no panel lights, no exterior lights, yet the horn will blow. I thought that perhaps the battery was dead and did attempt to boost the car using our RAV4 -no luck at all. There is some spark from the battery when the jumper cable wires are touched (pos to neg).I find it stranage that the horn will blow, but no panel lights will come on (with the ignition switch engaged) -I thought that there would be some lights if there is suficient charge in the battery to blow the horns.
I have checked for loose wires with no luck, and the fuses are fine. I am now a bit concerned that I may not have attempted the boost proces properly, although I did the pos to pos, neg to neg connections. I know I didn't leave the headlights on when I parked the car -it was daylight, and I was doing some interior work on the car that evening and would ahve noticed (not to mention that the car has a small buzzer that sounds if the lights are turned on without the ignition switch being activated.

Help!

Thanks
Doug  

Answer
Doug,

I don't have a TR3 wiring harness in front of me but it sounds like someone has been doing a bit of "improving" along the way.  The headlight warning buzzer wasn't an original item, for one thing.

The first thing to do is to get a decent voltmeter.  They're usually $10 or so for a cheap one at the local discount supercenter... or you can buy a nicer one for lots more.  The most important thing is to get one that'll handle 20v DC.  

Verify the battery voltage and polarity.  Then start tracing to the ignition switch.  What you describe sounds like either the fuse feeding the switch is bad or the switch itself may be bad.  Keep in mind that the Lucas fuse block contacts are all separate pieces of metal, so it's possible to have a good fuse and only have the circuits on that fuse working.


Cheers,

Jim