Wiring the Overdrive Switch

[Bumpa]

Excuse my ignorance, but I am new to Dolomites. I have bought a new O/D switch and wiring harness for the gear lever. I can't see how the wires are meant to be attached to the switch. In the blurry photo you might see what I have got. The wires end with small hollow round connectors, whereas the switch has no corresponding terminals onto which you could plug these connectors. How is it normally done please?

Mike

[Mad Mart]

They get inserted vertically on the nearest connectors to your hand. Slide the slots of the terminals on the wires over the copper terminals in the switch.

[Bumpa]

Ah, I think I see. Having inspected the hollow ends of the connectors with a magnifying glass I now see that the connector is slotted so it can slide along the blade in the switch. The plastic sleeve over the connector gets rucked up doing this and tends to force the connector off the blade, so I suppose I could slit the plastic for a centimetre or so. Weird arrangement if you ask me!

Since the O/D solenoid draws around 2 amps, I think a relay in the circuit would help preserve the switch, which is marked Lucas but I'm guessing was made a long way from these shores.
Mike

[Galileo]

J type OD solenoid does away with the relay precisely because of that low current.

[Jon Tilson]

The holding coil draws 2 amps but the engaging coil draws more and the insulation is needed because of high voltage transients.
In short the whole thing acts like a mini ignition circuit and it will short out to you via the stick, especially if your seats are soggy.
Trust me I know.... as the spit has on occasion been caught by a shower with the roof off.

A relay on the stick switch part may be a good idea, but its a lot more wires all in the same hostile environment. A better quality stick loom
than cheap 2 core lighting cable is the better solution. They cant even be bothered to change the colours!

Jonners

[GrahamFountain]

I was looking at something like this cable http://www.ebay.co.uk/itm/161994835583?var=460958355384, at least for near the base of the stick where it gets abraided. But where would one get the connectors for the switch end?

Graham

[soe8m]

Graham,

You can get rid of your gearstick with this cable and only have to screw the knob on the cable end. It is 12mm thick in diameter and so sturdy you can probably change gears with it also.

Use some ordinairy thin wall wires of 0,75mm2 or 1mm2 and it goes fine. The PVC type wires do break and are less flexible but the modern (1995+) thin wall are fine. If it makes the mind less stressful about this you can even use a little piece of heatschrink around the wires where it does leave the gearstick.

Jeroen

[Bumpa]

Thanks everyone. I think I will look for better cable for the gear lever switch. I like Jeroen's idea of modern thin wall cable. I was surprised to see the ordinary household twin core that was sent to me from Rimmers. As for a relay, I am a great fan of them and will put them on the headlights and heated rear window, so might as well use one for the overdrive too. You don't need any extra wires in the gear stick. The relay can be mounted remotely.
Mike

[GrahamFountain]

You can get rid of your gearstick with this cable and only have to screw the knob on the cable end.

They do thinner versions, and I reckon it will take a while for the remote mechanism to eat through the armour on one of those!

Graham

[GrahamFountain]

You don't need any extra wires in the gear stick. The relay can be mounted remotely.

You still need extra wires down to the side of the box, and they are a liability in their own right.

The TR7 has a similar falibility where the reverse light switch wires touch the exhaust. That's even worse in a way, because it takes out the windscreen wipers and the indicators if it happens, even if your in a forward gear - as I found out once in the rain. At least, in my case, the overdrive wire problem only takes out the CD player and the reverse light (the CD player matters more).

Graham

[Richard the old one]

I am sorry that I am a bit late with my comments but I have not had a regular internet for some time.

My 1500HL dolomites are used regularly and have been fitted with standard domestic twin lighting cable for a long time, at least 20 years, without any further failures. It is the twin sheathed heat resting type that is used for lighting pendants and care has to be taken to ensure that the sheath is passed out through the top of the gear stick lever so that it protects the inner cores.

[oily66]

If you go down the relay route then you could also use a telephone handset cord.
Fully designed to be pulled and pushed all over the place withstanding all sorts of abuse.