Cold Start indicator

[slowmo]

I don't have the manual in front of me, but my cold start indicator is on all the time. What is this even for and is the indicator triggered? I am going to tackle gauges and indicators one after the other since none of them actually seem to function.

Thanks.

[lumpydog]

Slo

It's a simple switch. It's clamped onto your choke cable. When you pull out the choke, the switch button pops out (activates the light) as the choke arm/knob is pulled out. Slide the choke in and it obstructs/closes the button, turning the light off.

This one should be simple - remove the 5 instrument panel screws and look for a small box clamped onto the choke cable immediately behind the instrument panel. It's probably loose or maybe slid out of place. The choke cable has three holes in it - two for bumps in the choke light switch box that keep it in place. One middle hole where the choke light switch button protrudes through - and toggles on/off with the slide of the cable.

[slowmo]

Ah. I thought there was a sensor somewhere which gave the indication to use the choke and that the sensor was kaput. Instead, it is just a reminder that you are using the choke. Silly me.

[siii8873]

some systems also have a temp switch at front of the engine near Tstat housing. You pull the choke cable which closes the switch discussed above. This switch is in series with the temp switch. So when you have the choke on and the engine reaches a set temp the choke (cold start) light comes on telling you that you have the choke pulled and the engine is warm.
Probably a problem with the switch noted above it is staying on.

[SafeAirOne]

Well, lumpydog's answer MAY be correct. Some engines had a simple system that merely went through the light switch then to ground as described by lumpydog, and some went through that same switch, enabling the light, then on to a temperature-activated switch (sometimes known as an "otter" switch) on the front of the engine, which illuminated the light by grounding the circuit once the engine is warm, reminding you to "turn off" the choke, so to speak...

http://www.coolcatcorp.com/Merchant5/graphics/00000001/ottalike1.jpg

[EDIT:] Bob beat me to it--I spent too much time researching the name of the thermal switch.

[lumpydog]

No otter switch on my engine. I wondered how that second temp sensor worked on trucks where I've seen it...

So, if he has one, it sounds like a simple way for Slo to test if it's a faulty otter switch - Would be to see if the cold start light is coming on right away, before the engine is even warmed up. Pull out the choke, and turn the start key to the point where the dash lights come on - but don't start it... and see if the cold start light comes on. If it does, that would point to the otter switch because it's grounding the circuit without the engine being warm. Correct?

But, even if it's a faulty otter switch, the the switch on the choke cable should be able to break the circuit if it's functioning properly...

[slowmo]

I have a sensor which has obviously failed closed AND the switch is closed as well. I looked on our hosts site and didn't find the sensor. Anyone have a link so I can replace it? Thanks.

[SafeAirOne]

They were used on other British cars. Jaguars and MG's come to mind. Google "otter switch" and do "images".

[slowmo]

The plot sickens...er...thickens. One of the PO's removed the switch completely. There is no switch. AND, when I disconnect the spade terminal on the otter switch, the light stays illuminated. So it is either shorted out somewhere, or connected to the wrong terminal. Well...at least this is not a mission critical glitch. Plan is to run new wires from the otter switch, the soon to be replaced water temperature sensor and the soon to be replaced oil pressure sensor.

I will then attempt to find the correct "otter" switch and attempt to find the bracket and switch assembly. Obviously this is not required and I could simply disconnect the light, but what the heck. I like everything tidy.

[lumpydog]

Slo - Our host has the switch you need (http://www.roversnorth.com/ProductDesc.aspx?code=RTC5816) and I think Ike carries them as well - as mentioned, it's a small box that clamps onto the cable. Make sure your choke cable has the provision for the switch. It should have three small in-line holes on the solid stem that protrudes through the dash panel. If it's a later model S3 choke cable, it may have the switch attachment point on the cable itself, within the engine bay. If you need a choke cable that has the provision for the switch - Ike carries them (they are not entirely easy to find and I do not believe our host has them).

[Edit] Added picture (borrowed from Ike's site) to show the three holes needed for the switch.

10812

[slowmo]

Thank Lumpy. Looking at the parts catalog it seemed there was a metal bracket which somehow held the switch on. Looking at the switch it seems to clamp directly on to the choke cable.

With the cost of the switch and an unknown cost for the correct otter switch I may utilize the warning light for my missile launching system instead.

[lumpydog]

Yeah - I think Ike has one with the correct metal bracket that clamps/secures it in place… The RN one appears to clip on.

[siii8873]

[QUOTE=slowmo;103983]Thank Lumpy. Looking at the parts catalog it seemed there was a metal bracket which somehow held the switch on. Looking at the switch it seems to clamp directly on to the choke cable.

the switch with the bracket is for earlier models, your vintage would have the switch on the cable as you note.

[mikeshaw247]

Well, lumpydog's answer MAY be correct. Some engines had a simple system that merely went through the light switch then to ground as described by lumpydog, and some went through that same switch, enabling the light, then on to a temperature-activated switch (sometimes known as an "otter" switch) on the front of the engine, which illuminated the light by grounding the circuit once the engine is warm, reminding you to "turn off" the choke, so to speak...

http://www.coolcatcorp.com/Merchant5/graphics/00000001/ottalike1.jpg

[EDIT:] Bob beat me to it--I spent too much time researching the name of the thermal switch.

Yep - I need this otter switch. I believe it is part number 545010 called a Thermostat Switch or Choke Light Switch. Different from the switch on the cable, which I removed. The switch on the cable tells you the opposite of what the Otter switch tells you. Otter switch says - hey - use your cold start. Switch on the cable says, hey, push in your cold start cable. Hard to find the otter switch. Rovers North doesn't seem to have it anymore.
Thanks!
Mike

[mikeshaw247]

Yep - I need this otter switch. I believe it is part number 545010 called a Thermostat Switch or Choke Light Switch. Different from the switch on the cable, which I removed. The switch on the cable tells you the opposite of what the Otter switch tells you. Otter switch says - hey - use your cold start. Switch on the cable says, hey, push in your cold start cable. Hard to find the otter switch. Rovers North doesn't seem to have it anymore.
Thanks!
Mike

I did find one. Yep - called Otter Switch, it seems everywhere. Now I just need to test mine to see if it's really broken.

Thanks all!
Mike

[westbound]

Hi all, great info in this thread. My 1975 SIII 109 has the otter switch (no wire attached), and what appears to be a previously replaced choke cable with no cold start cable switch. The wires behind my cold start dashboard indicator light were cut. Does anyone know if the otter switch and choke cable switch were meant to exist together, or was it either/or? If they were meant to exist together, does anyone know the correct way to wire everything up?

[roverp480]

The otter switch and cable switch work together , and are connected in Series. Wiring goes from ignition switch , through the warning light, then the cable switch and finally connected to the otter switch which completes the circuit to ground when the engine up to temp. Both the cable ( Choke operated) and otter ( Engine Warm) switches need to operate to illuminate the light. During the S3 production the otter switch was deleted and just the cable switch retained, which meant the light illuminated whenever the choke operated.