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Headlamp Pull Switch

PostPosted: Wed May 04, 2011 2:27 am
by brandon
I'm trying to sort out the leaky bits in the headlamp system, and am planning on ordering new nylon tube, vacuum cylinder, plastic elbows and "T"s etc. Is the headlamp pull switch (on the dashboard) a usual suspect for leaks, or a less likely place to consider? It does not look like it would be fun to get out if I have to replace it.

brandon

Re: Headlamp Pull Switch

PostPosted: Wed May 04, 2011 8:08 am
by Dave Fowler
Hi Brandon,

I'm assuming from your post that your car is a non-failsafe model, as is mine. In other words, the springs pull the headlamps down and the vacuum system raises them. If it's got the later failsafe system, which works the opposite way, none of the following will apply!

I reckon the first thing to check is the vacuum pods. I had a problem with the headlamps on my car and found on investigation that the nearside pod was to blame. The diaphragm within the pod deteriorates over time and springs leaks - this is exactly what happened to mine.

A quick way to check is to use a spare piece of pipe to connect to each pod in turn and simply suck air through the pipe. If the headlamp starts to rise and the vacuum holds when you put your tongue over the end of the pipe, then the pod's OK. For the nearside pod, you'll need to block off the outlet leading to the offside one, or else you'll be trying to lift both headlamps at once - plus, of course, you won't know which of the pods is faulty if they don't lift.

If it is one pod or the other, you can get a new one (not cheap, but it's what I did) or attempt a repair to the old one (too tricky for me, hence the outlay on a new one).

Good luck!

Dave

Re: Headlamp Pull Switch

PostPosted: Wed May 04, 2011 5:30 pm
by Jason1
Hi
Have a look at: viewtopic.php?t=13457

There is not much to the switch just a curved bit of metal as a spring and a rubber block. If you take the switch apart you will find the rubber has gone hard, rub it down with some sand paper to remove the hard surface and smear it with rubber grease and you are back in business.

Jason

Re: Headlamp Pull Switch

PostPosted: Wed May 04, 2011 6:31 pm
by brandon
Thank you Dave,

Mine is actually a failsafe model, but I think your checks are equally applicable and I appreciate the input. My suspicion is the vacuum pod, but I think it makes sense to renew at least some of the rest while I?m in there. Plus as you say, the cylinder is expensive.

That's perfect Jason. Exactly what I needed.

brandon

Re: Headlamp Pull Switch

PostPosted: Wed May 04, 2011 8:53 pm
by Jason1
No worries.

I found a few pics of when I did mine.

As you can see Lotus kept it simple.

After I did mine I put a cable tie around the main body to give it extra clamping pressure.

Jason

Re: Headlamp Pull Switch

PostPosted: Wed May 04, 2011 9:41 pm
by rdssdi
I replaced my +2 headlamp switch with a universal electrical push-pull switch and installed a solenoid valve in the nose to control the vacuum. My failsafe system will slowly open once the engine is off. As all the parts have been replaced save for the check valve in the fitting on the manifold I consider that the offending part. It very well may be fouled with carbon and dirt. When I have time I will try removing it and soaking it to clear it out. Possibly a squirt of cleaner may do the trick.

Bob