The Triumph Dolomite Club - Discussion Forum

Richard the old one wrote: ↑Mon Aug 14, 2023 5:21 pm In answer to how does the choke warning system work.

I was surprised to read the statement that the switch, part number 127607, has only one wire going to it so I have been looking at the spare bits I have. The switches I have seen all have two connections. One is for the white with blue wire that comes from the warning light cluster and the other is for an earth connection. The switch is very basic, it has a little plunger. The white bit in the photograph, See Switch fitted to cable, which when pressed in opens a contact and the earth path is lost and so the warning light goes out. It is critical to locate the switch correctly on the choke operating mechanism which has two locating holes drilled in it for locating bumps which are mounded onto the switch body, between the two locating holes there is another slightly larger hole for the switch operation plunger to fit into it. It is possible to think that the switch is located correctly when it is in fact needs to be rotated slightly for the holes and the locating bumps to line up. I also think a switch could accidentally be turned over a period of time and this could cause it not to work correctly.

I believe there are two types of choke controls/cables used on Dolomites. One you pull the choke knob and then have to turn it to lock it in that out position. The choke knob has a shaft which is attached a smaller diameter multi strand cable. When the choke knob is full in, no choke, see photo No Choke, the diameter of the shaft is such that it presses the plunger in and the switch contact is open. When the knob is pulled out the larger diameter shaft is pulled out of the way and is replaced by the smaller diameter multi strand cable. See photo choke in operation, his no longer applies pressure on the plunger so the switch contact makes which bring on the warning light.

The other type of choke cable I have come across also consists of a knob with a shaft but the shaft has a slot cut up its length into which the switches plunger can fit when the choke knob is rotated. This type does not have a small multi strand cable attached but has a solid wire. It relies on friction between the solid wire and its sheath to keep the choke cable out and stop it rotating when it is pulled out and turned. Over time this friction can reduce and a common way around the problem was to use a washing line peg to keep the choke knob out. What I have found is if you bend the sheath / cable in the engine compartment and then release it this will normally increase the friction of a time.

Richard the old one wrote: ↑Sun Aug 20, 2023 8:13 pm The switch shown is from 1977 or later 1500hl Dolomite but I believe the switches are common across the range. Have you taken the switch off and checked to see if it operates and to find out if the bits you have would operate a new switch. If you just earth down the wire you have taken off the choke warning light should come on provide you have the ignition switched on, if it does not you will know it is more than likely to be the bulb has failed or gone black.