Cold Start Light / Choke Cable Switch

Technical questions and answers
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firemanshort
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Cold Start Light / Choke Cable Switch

Post by firemanshort » Tue Nov 15, 2011 2:30 pm

I keep leaving my manual choke pulled after I start out on cold mornings. I usually remember after driving half way to work. :(

I know that the cold start light on the instrument bezel is supposed to indicate when the choke is pulled through a switch that clips to the outside of the choke cable and some sort of temperature plug on the engine.

Unfortunately, my truck only has the cold start light - but no switch on the choke cable and no temperature plug on the engine.

On a possibly related note: I have never been able to figure out what these two plugs are connected to. (see photo) They have never had anything plugged into them since I owned the truck. The truck wiring is largely stock but does show occasional evidence of repairs or improvements. The wires disappear into the wire loom and I have been unable to trace them. I have placed both 12v+ and ground on the wires and even shorted them together to no witnessed result.

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My questions;

1 - does anyone have a functioning cold start light and can you photograph the components? Does anyone know the part numbers or know of a supply house that sells these parts?

2 - does anyone know what those plugs are for? Are they part of my missing cold start wiring plan?
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sebking
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me too!

Post by sebking » Tue Nov 15, 2011 6:19 pm

That's something I'd like to know as well
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1982 Stage 1 v8 SW
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Geoff
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Post by Geoff » Tue Nov 15, 2011 6:29 pm

Yes, I have a functioning cold start light, though the switch has been missing from every Land-Rover I have ever bought when I bought them. However they are easily available (although at a silly price for what they are) - the part number is RTC5816. Go here (a very useful site):



http://www.landroverworkshop.com/

and insert the part number or 'choke switch' and you will find a number of suppliers. Of course, you have to have the right choke cable with the necessary holes or the switch won't work.

If you short the two wires that connect to the switch together, the orange choke light should come on, but only of course if one is correctly connected to the bulb, and that is working (and is in turn connected to the vehicles electrical power supply), and the other is earthed. On some vehicles, the earth lead from the switch goes to a temperature sensor on the engine, which means that even with the choke out the light will not come on to warn you to push it in until, in theory, the engine is up to normal operating temperature. If you have one of these and it doesn't work satisfactorily (or you simply want to be reminded whenever your choke is out and make up your own mind about whether the engine's warmed up enough) you can simply bypass this by connecting the earth lead from the switch to any good earth point (I use a nearby bolt on the wing).
Last edited by Geoff on Tue Jan 17, 2012 1:00 am, edited 1 time in total.
2 1981 Stage One 109 V8 SWs
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Geoff
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Post by Geoff » Tue Nov 15, 2011 6:42 pm

More interesting (to me) is the following phenomenon: I removed the choke switch from my non-Stage 1 Series 3 to borrow it for my most recently acquired Stage 1 (which of course didn't have one - see above) - with the engine off, the light didn't work - of course - no switch - no connection - but when I started the engine, the light came on - ok, a short somewhere - then I pushed the choke in, and the light went off! Not believing my eyes, I pulled it out again, and the light came on again!! Go figure - I tried it several times. So I now have a working choke light switch with NO switch! Talk about the ghost in the machine - if I knew what was going on, I'd patent it! :shock:
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map1275
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Post by map1275 » Tue Nov 15, 2011 9:20 pm

Reading the workshop manual and identifying which wire colour and trace colours you have will tell you what these wires are for.
Also what original terminal design they are will also narrow down the possibilities. However this isn't covered in the basic Land-Rover diagrams.

As I think you are pointing at two 1/4" female Lucar terminals, I would suggest these are for the stop light or choke warning light.

As with many parts for your car they are readily available in the US. An interchangeable part was used on most North American spec midgets etc.

The correct part for your car is readliy available under two part numbers. One with the retaining clamp, screw and nut and one that is just for the switch.

The Minimetro part will also fit however like many it has short lenghts of wire already attached to the switch.
Last edited by map1275 on Wed Nov 16, 2011 1:18 am, edited 1 time in total.

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Post by map1275 » Tue Nov 15, 2011 9:22 pm


Mrs Bingham
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Post by Mrs Bingham » Wed Nov 16, 2011 10:15 am

In answer to the question in the original post:

1) Yes, I have a working cold start light. The part number is as quoted by “Geoff” and is readily available through several suppliers. Mine was originally broken and I was able to source one easily although the one I got clipped on to the choke cable as opposed to using a retainer. I used some small cable ties for assurance.
2) Those plugs are for the choke light and where you see the choke cable there should be a solid 4” section of shank on the cable. If you feel around it you should feel a small hole – the switch would locate over that with the switch plunger slotting into the hole.

The wiring is simple:

Switched +12v (ignition feed) – Bulb – Switch Terminal (doesn’t matter which one). Other Switch Terminal – Thermal Switch on inlet manifold (see pic below). This switch goes to earth when warmed up.

Note* the light if wired correctly will only illuminate when the choke is out and the engine is warm unlike other BL cars of the day. If you have no thermal switch present on the manifold then afixing the cable straight to earth would be an acceptable solution where the light will now illuminate at any time the choke is pulled with the engine running regardless of temperature.

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disco2hse
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Post by disco2hse » Thu Nov 17, 2011 3:41 am

And, the temperature it switches at is 30ºC. Sufficient for your engine to run without the choke.
Alan

1983 ex-army FFR 109 Stage 1
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Post by map1275 » Thu Nov 17, 2011 11:07 pm


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firemanshort
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Post by firemanshort » Fri Nov 18, 2011 2:53 pm

Good stuff - Thanks!

Since I am running an Edelbrock intake - I will not have the thermal switch.

I am heading to the UK for Christmas and I guess I know what I will be putting on the Christmas list :roll:
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disco2hse
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Post by disco2hse » Fri Nov 18, 2011 7:40 pm

I would think that since it is only a temp sensor you could put it pretty much anywhere you want (that is sensible of course). There is no reason that you could not drill and tap a hole in the Edelbrock inlet manifold, for example.
Alan

1983 ex-army FFR 109 Stage 1
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datsta
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Cheap cure for the thermal switch $US 2.59

Post by datsta » Tue Jan 17, 2012 12:07 am

I have two of the choke thermal switches and neither of them work. You don't seem to be able to pull them apart like the cable switch.

A nice man on ebay sells 'KSD301 Temperature Switch 35 degrees' for $US 2.59 including postage. Just epoxy it on top of the old switch and hook up an earth wire on one of the two connectors. The switch closes at 35 degrees, same as the LR one. He is in Hong Kong so when you search ebay, search 'Worldwide'. Mine arrived in 13 days to NZ.

Suggest you search ebay for 'ksd301 35 NO 1pc' or this link might work http://www.ebay.com.au/itm/170529324388
Stage 1 V8 hardtop s/w.

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