One dim brake light

[Darrell O]

Hi there, the LH brake light on our Ventura is dimmer than the right. Both bulbs are a matched pair.

What might be the smoking gun to look for? I think it would be simpler to trace if the light stopped working completely.

Thanks everyone.

[Bobbie Mayer]

I bet it is the same problem I had- wires connected backwards. The brake light is brighter than the tail light by design and if the wires are switched it can do this.

[Bob Miller]

Are both the stop and tail lights dimmer? If yes, look for a bad ground, if no look for a dirty contact in the socket or a bad splice in the one wire.

BTW: Did you verify that the correct bulb was being used, there are two different tail/stop lights of the early bayonet base design, one with offset tabs the other with even Tabs. It's possible to put either one in backwards.

I have never heard of "Matching Bulbs" I'd also try switching the left and right bulb and see if the problem moves.

Good Luck

[KevinPete]

Ground may be poor or intermittent on that one socket. Run another wire from the socket ground to a known good ground, see if it's properly bright. If it is, check all connections and clean your ground connection. If not, might be a wire issue as Bobbie says.

[mary and bob]

or a bad ground or bad connection in the bulb socket. There is a little wire brush made for cleaning bulb sockets and the contacts.

[Eddie Longest]

Some light sockets will let you install light backwards. Check the depth of the light locking pins and depth of the socket. Easy first ck.
Eddie

[Dudley]

The tail lights on the Ventura just have a ground wire that is just wedged behind the mounting plate. I think that it needs cleaning or do what I did, crimp a wire connector on it and screw into the plate(after sanding the plate) That should give you a better ground. If the ground is bad, the bulb will get its ground by going through the park light filament to ground in the other taillight , which will act as a resistor , lowering the voltage to the bulb,thus dim light.

[Dan Meyer]

I've had that problem, and the issue was a dirt accumulation on the inside of the tail light lenses.

Best of luck!

--Dan Meyer

[Byron Kinnaman]

We all know that all electrical problems and those concerning light are "ground" problems.

[Roger C H]

In England and maybe in Canada, they are "Earthing" problems. LOL

I fixed a similar problem on a '59 Ford only it was the front directional lights. Dudley analysed the problem.

In this case, the right turn signal worked, but the left turn signal turned on both parking lights. The current to the left was feeding the bright filament and not finding ground or earth on that side, found a path through the common ground on the bulb, back through both right and left parking lights to the good ground on the right side.

[Dudley]

only an "earthing" problem in Canada when working on Lucas based cars! I owned a few, Mki cortina, austin mini, austin america. Then I figured out they were a pain!

[Darrell O]

Wow, thanks everybody! Consensus indicates that it may be a ground issue. The bulb socket is clean and coated with dielectric grease - and even the lens is clean. LH and RH bulbs are new and sourced as a pair from the same package.

I'll start with Dudley's VENTURA-centric suggestion and work back from that. All the wiring is buried under panelling so I hope that the fault is in the light or just inside the mounting plate.

[Ian G.]

Originally Posted by Dudley

only an "earthing" problem in Canada when working on Lucas based cars! I owned a few, Mki cortina, austin mini, austin america. Then I figured out they were a pain!

LOL I bought that Lucas wiring smoke by the case, used it oon my collection of MGs, Austin Healey, Mini Cooper, Cortina, ....
Yes check your grounds.

[Dan Meyer]

Swap the bulbs side-to-side. If the problem follows the bulb, replace both of them. Otherwise, keep looking for a wiring problem.

-- Dan Meyer

[Darrell O]

Like Dudley says, it's the ground.

Back in 1976 the rascals at the Ventura factory merely stripped the ends of the ground wires and shoved the exposed ends in behind the metal strap that holds the light sockets.

As you might imagine the copper and galvanized metal were corroded and loose by now. I crimped proper ring terminals to the ground wires and screwed them to ground good and tight.

[Dudley]

patting myself on the back