The Triumph Dolomite Club - Discussion Forum

Hello All,

I am after some assistance please with regard to an electrical issue that I am experiencing, and unfortunately electrics is not a strong point...

I seem to have something a little odd in respect of the front lights and their operation. So situation is as follows:

• Side lights come on fine at the front.
• When you put on the main beam the passenger side light dims. Both main beam lights are on at this stage as you would expect. Drivers side light fine.
• When you then put on the full beam, the passenger side light remains dimmed and the main beam light also dims… Drivers side fine.

Rear seems OK although the passenger rear light is dimmer than the drivers side which is nice and bright.. Have swapped over bulbs and tried new bulbs at the rear but it remains dim on the passenger side..

My initial thinking is that this could be just a bad earth somewhere or could it potentially be something more sinister? If it is a bad earth are each of the lights individually earthed or is there just one earth point and if so where is it??

As supplementary information and probably not connected, but the hazards also don’t work. When you press the hazard switch, one side (passenger) flashes but nothing at all on the drivers side. I assume that this is more likely a duff switch but could it be linked to the lights at all? I intend to test the switch.

Any ideas, suggestions or help would be appreciated.

Thanks in advance..

James

Hi James, definitly a bad earth, i would run a seperate earth to the lamp. That is the easy way. Otherwise trace all the wiring back till you come across the annoying item. I take the easy way as electrics are not my strong point.

Tony.

Agree completely with Tony, it's an earthing issue. With the simple electrics on 1970s cars it really couldn't be anything else. The headlights have separate earth wires which will be attached to a bolt in the body somewhere (I can't remember where). Just follow the black wire back from the lamps. That connection could be rusted or just cruddy preventing full current flow.

The side lights and tail lights probably earth through the lamp body, which is always a silly idea. Get some black wire and provide each lamp unit with a good earth connection. Take the black wires to a clean bolt fixed into the body at a clean unpainted point.

I had someting like this earlier in the year where the lights not working right.

With the front ones there is a connector block down by the front valance where water had got in and corroded the wires , I clean them up and all was good.

With the rear lights they earth through the lamp holder and the lense, I cleaned the lense unit and bulb holder and all was good.

Hope this is of some help.

Thanks everyone. Happy to hear that all of you point the issue to being a bad earth and not something else!

Shall take a look at the weekend if it isn't too warm!!

Thanks again, really appreciated.

Just a quick add on to all that has been said.

Yes earth problems indeed, i'd be looking at the back of the sidelight itself as these are very prone to weather, rotting of the rubber boots on early cars which also had a bullet connector holding the earth wire to the lamp body! !!!!!!

Nearly ALL the earthing for the whole front loom is done through a ring terminal bolted to the N/S shock tower under the bonnet (and sometimes and some models, one on the matching spot on the offside) But most earthing faults are thankfully NOT in the loom but mostly in or close to the lamp units themselves.

The tail lamp problem could simply be reversed wires on the bulbholder or a bulb forced in the wrong way round so you have one sidelight and one stoplight on. The sidelights aren't very bright at the best of times, if one IS, i'd suspect it's actually a brake light!

Steve

Thanks Steve.

Planning to whip the side lights out for an inspection after your comments so thanks for the heads up!

In respect to the rear lights sometimes the earth path within lamp holder can give a problem. The way to correct this is to solder as shown in the following photograph.

Thanks Richard.

Will take a look at this as well. Much appreciated.!