Electrical Question

[jrcoolt]

I ended up getting that TR7 that I made a post about a little while ago. Now I have an electrical question. How does the electrical work? Does everything run off the battery and the alternator charges your battery, or does everything run off the alternator?

The problem I am having is when I turn the headlights on, they just go up and down, up and down. And also, the radio just flashes on and off. I have one more thing. The switch under the dash that you need to turn on to start the car, when that gets turned off, the engine revs up. Thanks if you have any feedback. Here are the specs.

1977 Triumph TR7 2.0L 4cl
5 speed Manual

Thanks

[bottomtop]

You fed it after midnight didn't you!

I don't actually have a switch under the dash like you mention. The behaviour you describe is very strange and seems related to either a number of individual problems, or just one big gremlin. This might sound really silly, but have you tried cleaning the battery terminals and alternator terminals?

If electrical problems involve the ignition and/or starting system, I would be a bit worried about the safety of the car, as I have been told that these systems use a lot of power and can be dangerous in the event of a short circuit.

[KRenken]

It sounds like you have several problems you're dealing with.

First of all, the switch under the dash is not stock. It most likely is something the po wired up for some reason...possibly as an anti-theft measure...or possibly as a "fix" for some other problem like an electrical short that was draining the battery.

Second, it sounds like you have dirty contacts or faulty diodes in the limit switches on the headlight actuators.

These cars have a tendency to have weak grounding points and corrosion in the electrical connectors. The best advise I can think of is to start by cleaning every electrical connection and ground that you can find.

I think you'll find that you will get a lot of help from this forum. There's a lot of folks here with a lot of helpful advise.

Kimmit

1980 DHC
GM 3.8 v6 fi

[FI Spyder]

It runs off the battery with the alternator charginhg the battery. If the battery is down and can't handle the load (ie. headlights) you'll see them brighten up asthe rev's pick up and alternator supplies more juice.

They is a motion limiting switch that stops the headlight motors when they raise into position. If this isn't working (dirty/worn contacts) they can continue going up and down. While I haven't worked on that system yet (mine continue to work like they're supposed to) that's the general explanation of how they work. Someone whose been through it may be more specific.

Switch under dash causing motor to speed up? This must be an add on by PO. Sounds like he didn't quite know what he was doing which begs the question what else is screwed up electrically. (See radio turning on and off.) Get an electrical diagram for your year and country (see jclays website and download pdf manual) and start tracing.



TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra