Timing light power source

[Greg S.]

The battery in a C3 is so far from the engine compartment that the power lead from the timing light won't reach the battery. Someone in a post said attach the power lead to the 12 volt source on the alternator. I assume the 12 volt lead on the alternator is the post under the black rubber boot in the attached picture. Am I correct. Is it ok to power the timing light from the alternator?

[Terry M.]

Re: Timing light power source

The battery in a C3 is so far from the engine compartment that the power lead from the timing light won't reach the battery. Someone in a post said attach the power lead to the 12 volt source on the alternator. I assume the 12 volt lead on the alternator is the post under the black rubber boot in the attached picture. Am I correct. Is it ok to power the timing light from the alternator?

Yes, the connection on the back of the alternator will work, so will the power lead (large diameter red wire) on the horn relay. So long as you don't short either connection to ground there will be no damage to the components from this use.

[Joe L.]

Re: Timing light power source

The battery in a C3 is so far from the engine compartment that the power lead from the timing light won't reach the battery. Someone in a post said attach the power lead to the 12 volt source on the alternator. I assume the 12 volt lead on the alternator is the post under the black rubber boot in the attached picture. Am I correct. Is it ok to power the timing light from the alternator?

Greg-------


I always use the power connection at the horn relay. Very convenient and easily accessed.

[Greg S.]

Re: Timing light power source

Greg-------


I always use the power connection at the horn relay. Very convenient and easily accessed.

i have spent about six months restoring the engine compartment, removed and replaced engine, rebuilt front suspension and more. I am embarrassed to admit that I don't know where the horn relay is. The car has dual horns. Can you point me to it?

[Patrick H.]

Re: Timing light power source

i have spent about six months restoring the engine compartment, removed and replaced engine, rebuilt front suspension and more. I am embarrassed to admit that I don't know where the horn relay is. The car has dual horns. Can you point me to it?

Nowhere near the horns.

Left (driver's) inner fender, ahead and left of your brake master cylinder.
Image Googled and linked below. Not the same year exactly as yours, but you get the idea.

2012-11-30_005015_69_corvette_fusible_linkk.jpg

[Bruce B.]

Re: Timing light power source

The battery in a C3 is so far from the engine compartment that the power lead from the timing light won't reach the battery. Someone in a post said attach the power lead to the 12 volt source on the alternator. I assume the 12 volt lead on the alternator is the post under the black rubber boot in the attached picture. Am I correct. Is it ok to power the timing light from the alternator?

I use a small 12v motorcycle battery on the floor next to the car.
Works great.

[Greg S.]

Re: Timing light power source

Nowhere near the horns.

Left (driver's) inner fender, ahead and left of your brake master cylinder.
Image Googled and linked below. Not the same year exactly as yours, but you get the idea.

[ATTACH=CONFIG]63602[/ATTACH]

On a 75 it is not on the inner fender. The AIM 12G sheet 1 shows it by the fuse block. Can't really tell if it is inside or outside but I don't remember seeing it. Now that everything is back together the power brake booster, evaporative fuel canister, wash bottle, clutch linkage and brake lines make the fuse panel almost inaccessible. I know I have a relay because horns work. Must be inside.

[Greg S.]

Re: Timing light power source

I use a small 12v motorcycle battery on the floor next to the car.
Works great.

Great idea. Thanks

[Bruce B.]

Re: Timing light power source

Why risk a short when a external battery will eliminate any potential problems?

[Frank D.]

Re: Timing light power source

My Actron digital timing light leads make it to the battery just fine. Now - keeping the leads off the exhaust manifold is the real problem.

[Leif A.]

Re: Timing light power source

My Actron digital timing light leads make it to the battery just fine. Now - keeping the leads off the exhaust manifold is the real problem.

But, the OP was talking about his C3...battery behind the driver's seat.

[Frank D.]

Re: Timing light power source

My bad. I know nothing about C3s...

[Jack M.]

Re: Timing light power source

When I bought my 1st Corvette in the 70's, I opted for a Self-Powered Inductive Timing Light (two D cell batteries)... worked great for the situation.

[Richard M.]

Re: Timing light power source

My Actron digital timing light leads make it to the battery just fine. Now - keeping the leads off the exhaust manifold is the real problem.

That's exactly how I fried the inductance cable on my dial-back Actron the other day. I repaired it but I think the pickup overheated and now it's junk. Called Actron and they don't sell parts. I hate Asian items like this as nobody can fix things anymore as the parts aren't available.

Looking for another one locally and not even my AAuto, AZone, or Napa stock them. I might have to resort to Amazon and wait for delivery.