TR2/3/3A TR3 Turn Signal question...

[Brooklands]

First off, when the previous owner modified the steering, he added a three way toggle switch on the dash for the turn signals. Once I got used to always turning them off manually all was well until last week when I noticed on a drive that I had no flashing light on the dash when the turn signals were on. When I got home I checked and I get one clicking sound on the first left turn flash as well as one flash on the dash, and then no more clicks or dash lights on subsequent flashes, but the left turn signals keep on flashing properly. There is no sign on the dash and no clicks when I flip on the right signals. The right rear flashes at double time and the right front signal does not work. I tried changing the front right bulb but that did not fix anything.
Is it the relay?
I thought I had one with a broken mounting bracket, but I seem to have tossed it when cleaning the garage, so I could not check to see if that fixed it.

 

[Mickey Richaud]

Dave - I've found that issues like this are usually related to poor grounding. Check that first.

G'luck!
Mickey

 

[Brooklands]

The two ground wires I found in this circuit seem to be solid. The right front light does turn on with the "side" lights switch but not with the turn signals. I probably could be missing other ground wires in the circuit...

 

[TR3driver]

Kind of sounds like two separate problems to me. I would work on getting the RF bulb working first, and then worry about why the dash light doesn't work.

My next step would be to remove the RF bulb, and carefully probe the socket terminals with a voltmeter or DMM, while the right turn signals are on. From the socket to one pin should give nothing, but socket to the other pin should show 12v flashing (in time with the rear signal). If not, there is a wiring problem to the socket. Back up to where the subharness joins the main harness (and the body ground) and check again.

If you do see the 12v flashing at the socket, then remove the socket from the grille and pull it out of the rubber boot (leaving the wires connected. Insert the bulb, and then test again at the outside socket terminals. If you now find the flashing 12v (but the bulb still doesn't light), either the socket or the bulb is bad. But if the flashing 12v goes away, then there is a bad connection somewhere up the line (which will pass enough current to power the voltmeter, but not enough to run the bulb).

FWIW, I had a lot of trouble with that socket being intermittant, until I realized that the wires were getting pulled tight when it was installed. Creating some slack in the wires made the problem go away.

 

[Brooklands]

I don't get 12 volts at the socket, but I am having problems following the harness as it was spliced several times in the past...I will return to the challenge this evening.

 

[TR3driver]

Normally, the wire from the RF turn signal runs through a short sub-harness up to the area behind the RH horn, where it joins with a GW wire from the main harness (2-way sleeve). The GW main harness wire runs from there over to the LH side, where it should be joined to the wire from the control head and another GW wire from the main harness (RR turn signal) (4-way sleeve).

Don't know if your car will match that, but those two junctions are where I would look next.

 

[mrv8q]

Had that exact same problem on my '3; turned out it was a bad bulb, although it <span style="font-style: italic">looked</span> fine..... didn't hurt cleaning up grounds, etc., afterward.