indicators and brake lights not working

Hi,

None of the indicators (front or back) or the brake lights work on my TC2500. There isn't even a clicking sound from the indicator flasher. My first thought was fuses, but the 3 fuses in the fusebox under the glove compartment are all good. (none of those fuses are for the headlights, is there another fusebox I haven't found?). Where should I be looking for the problem?

usually when I have a problem like that it turns out to be a dirty/corroded/bad connection at the fuse box. Either the tabs that hold the fuse are funky, or the spades on the sides of the fusebox are funky. I actually got tired of messing with those bad connections and bought a new fusebox.

The fusebox is the first place I'd check for the problem.

Second place I'd check (really my first) is a bad ground. If you have a multimeter (combination volt meter & ohm meter) then it is just a matter of checking methodically from one end or the other.

Verify there is a ground at the lights then either start at the fuseblock and check until you don't find power or start at a light and check until you have power.

As for other fuses -- I've never owned a Triumph that had the headlights fused.

Hello Wombat,

Firstly the lights are not fused.
The fuse that supplies the indicators and the brake lights also supply the reversing lamps and the fuel and temperature gauges so if those work your fuse is OK.
The simplest to check is the brake lights, assuming the reversing light and gauges work, the switch is under the brake pedal, just remove the two wires and short them together with a piece of wire, switch on the ignition and check the lights. Look at the lamp(s) earthing if yoiu have nothing.
Likewise a simple check of the flashers is to short out the wires at the flasher relay (Under the dash on the inside of the A post
I think, about where your left knee is maybe a bit higher)
Select left or right on the switch and both front and rear should be on, if not earths or lampholders.

See how you get on, no luck with a diagram? If you are struggling I could scan mine but can't guarantee the quality.

Alec
2.5P.I. Mk 1

Thanks guys, I'll do all that this evening (unless I bottle my homebrew, in which case it'll have to wait until tomorrow evening!).

There are two flasher units close to the fusebox under the glove box. When you say "about where your left knee is" I assume you're talking about a left-hand drive car? Mine's right-hand drive.

I haven't found any diagrams anywhere despite many Google searches: I'd really appreciate it if you could scan yours for me. Thanks very much!

Hello Wombat,
Yes I was assuming LHD. Please let me have an E-Mail address so I can send the scan, also please let me have the year of manufacture.

Thanks,

Alec

Thanks piman, I've sent you an email, so you can reply to it with the scan. The car was built in 1975. Thanks very much!

I went out and had a play with a multimeter and a head-torch (it gets dark early now that daylight savings has ended). This is what I've found:

The reversing lights and guages work so the fuse is good.
The indicator and brake lights themselves are properly grounded.
When I short out the brake switch above the pedal (with the ignition on) the lights don't work.
Neither wire going to the brake switch is positive.
I've identified which of the two flashers is for the indicators.
One of the wires going to the flasher is positive (12V).
The other wire going to the flasher is normally not grounded, and it connects to ground when the indicators are activated at the column switch.
The flasher never makes a ticking sound when the indicators are activated.
The flasher is not open-circuit when I check the resistance between its two terminals (with both wires disconnected).

The plot thickens!

Hello Wombat,
you should have power on the green wires (2, probably crimped onto one connector) at the brake light switch with the ignition on. As the gauges are downstream of this then that must be live. Carefully check that connection.
Unless there has been some alteration in the past to the wiring.
Diagrams have been sent to you so I'm sure that will make it so much easier.

Alec

Thanks for the awesome scans! They will be a great help.

All fixed now. The problems were a combination of dead flasher units and dirty switch contacts. The scanned wiring diagram made the whole job a lot easier