Electrical problem from hell, divine guidance required.

[berni29]

Hi All

I am trying to get the electrics on my car to work. It was rewired by someone when restored in the early 90s. I have added an earth in the boot, cleaned, and added one on the engine. The engine turns over really well on the starter (poor compression or a good starter not sure which). I have also soldered and cleaned the 5 earth wires behind the dashboard that go to the chassis bolt.

The real problem is that when I touch the electric windows (which crawl at best) the headlights dim by 75%. Also the hazard light (on the dashboard) flashes briefly on. There is a non standard looking relay that clicks pathetically behind the dashboard when the window switch is clicked. I have not had the relay out yet. Did they have them as standard? When not touching the window switch the headlights seem OK. I crashed and wrote of my last plus 2 in part because of the bad headlights (another story) and absolutely have to fix this. I have some H4 headlights arriving soon but no point fitting them at the moment! I have not touched any of the relays under the bonnet yet. Someone suggested changing them for modern units. I have a 1971 +2s with the relays in a line on the passenger side (RHD).

Actually the windows have stopped working altogether at the moment and I just get the relay click. That is with no lights or anything on. The alternator works, and the headlights brighten when the car revs.

Almost everything electrical on the car works. Just not very well.

Any help much appreciated!

[nebogipfel]

Berni,
Not sure about the non-standard relays but on the subject of slow (stopped) windows, are they just tight in the runners and therefore drawing far too much current?

In that case it often helps to get an aerosol of silicone spray (the stuff designed to make plastic trim shiny) and spray it into the runners. The result is usually much less drag.

It might make the windows go up and down the typical slow rather than slooooooow!

[berni29]

Hi Nigel

They do not seem tight, and both windows behave exactly the same way. I will give it a go though. I just got the relay out from behind the dash and cleaned the spade connectors. The windows now work again at their pathetic pace accompanied by the heavy dimming of any lights that are on, when I tested it just now it was the interior light that dimmed by 50%. Is that a symptom of windows that are taking too much current, or does it sound like a bad earth?

Many thanks

Berni

[Elanintheforest]

Hi Bernie
This is a problem I get every year in the winter with Jags with electric windows...damp gets into the motors and shorts them out or at least slows them down considerably. A quick fix, if it's the same problem, is to remove the door trims and use a hairdryer to dry them out. Your missus will think you've gone barmy taking a hairdryer to your Elan but it may just work! While you're there disconnect the bullet connectors to the motor at the door hinge and give them a good clean and vasaline. Even more for your missus to worry about then! A fan heater in the cab may help as well, just to get any damp out of the dash switches.
Mark

[berni29]

Hi Mark

Thanks for the suggestion. When suffering from this problem is the current drain such that it affects the brightness of the headlamps to a meaningful extent?

Berni

[nebogipfel]

Sounds like they are drawing lots of current. Could be the runner trick will help but as mark says the motors may also need attending to and as he says it would be well worth cleaning the bullets while you are in there

I would guess to cause the light dimming which suggests high current drain the motors would have to be running tight due perhaps to corrosion?

My mate with a +2 swears by the silicone spray for his windows

[Elanintheforest]

Yes, lights go dim when the window doesn't work at all...haven't noticed when they are just slow. The silicone spray on the runners is only really used to lubricate the dirt, moss and grit in old runners. The trouble is you can end up with a sticky mess that will attract more dirt and grit and over time make the situation worse....but it will work in the short term! If the runners are original they will be well past their designed life....replacement is the only long term solution.

[lotusanglia1965]

HI Berni!
on the baby elan we built recently, the window motors were very slow and took a lot of current. we stripped them expecting to find worn/knackered innards,only surprise was that they were barely used. brushes looked new. we summised that as they are motors,originaly designed to run for a while, they weren't run in yet,even after eight years of use. after reassembly i left them in a vice,hooked up to a battery for a few hours. when back in the car they were excellent, never seen a lotus window move so fast! worth checking wiring first though.
Martin

[1964 S1]

Posted: 04 Jan 2006 11:31 pm Post subject:

--------------------------------------------------------------------------------
I'm no expert but I don't think your light brightness should be affected by rpm with an alternator. Generators yes, weak battery, yes. Maybe the idle speed is a tad low or loose belt? My windows draw a bunch of juice, lights definetly dim, I've got an original generator, I've got an older battery. In your Earthing Points question I wrote...(not to be repetetive but it seems more applicable here.)
"It could be your window motor. My '69 +2 has always had a sleepy driver's side window, I pull and push a bit to help it along, the passenger's side works great. Also, if moisture has gotten inside the door, corrosion on the regulator hinges can make for slow movement, and eventual motor burn out. I'd pull the door panel and lube everything in sight, (including door opening and lock mechanisms,) I use spray lithium grease and a toothbrush. Finally, check the vertical window channel alignment. Lubing the ends of the glass can free them up also. (a little WD40) "

[berni29]

Hello all

Right, I am going to have a good look inside the doors and do a big lube up! That must help. I will be checking the electrics as much as possible as well. The help is really appreciated. At least now I have a list of things to work on rather than standing there wondering what next!

I will let you know how it goes!

Berni

[JJDraper]

Just to make you all feel better, I used to think my windows were slow until I gave a lift to my mate with a modern TVR. He was envious of the super-speedy windows in my old +2.... Speed is always relative.


Jeremy

[twincamman]

check your alt or gen out put sb around 14 volts on vt meter --or the condition of the battery [may be buggered ] ---- ed

[john.p.clegg]

Try connecting the battery(or a decent 12v supply) direct to the wires to your window motor,you may be pleasantly suprised ts

John
P.S.
my delete button isn't working again

[berni29]

Hi John

Good idea, I will try that. I have been mucking around with the headlight pods and am going to add a failsafe bar to mine (I have non failsafe). I really dislike the headlights going up and down at different rates, although I do not mind them being non-failsafe.

I am going to measure the alternator output tomorrow. The battery is in good condition. I think that it is normal for the headlights to brighten a bit as the engine comes off off idle (unless it is to stall!)

Many thanks

Berni

[type26owner]

Berni,
Thomas Edison found out the hardway the limited capabilities of direct current. (Tesla is da MAN that created our modern day world!) Measure the voltage at the headlamps and at the starter while the lights are on and the engine is off. If there is too much resistance from bad connections or the wire is sized too small the lights will be dim or when another load is introduced on the battery. Typical good value will be only one volt between those two places but I'm going from memory on that call. Now do the same thing with the engine running at about 2000 rpms and the alternator is contributing. The voltage drop should be nearly the same.

The lamps get dimmer as they age. Replacement should be about every 100k miles if you need the lights as bright as new.

I don't know the S3 wiring loom but on a S2 the headlights are on their own separate circuit. If it dims with another load, it's ever so slightly. This effect is very much temperature sensitive though. The colder the battery, the less it's instant output in current will be. There might be better choices of batteries depending on the ambient temperature where you live. What I would be suspect of though is the battery cables and battery cable connections to the battery. They can and will commonly measure no voltage drop but when a current load is applied their resistance shoots up. You'll need to have an inductive type ampere meter to measure this though. One dead giveawy that it's the cable is at the connection there is any sign of white corrosion on the copper stranded wire under the insulation. Replace immediately cause they're cheap and see if the problem goes away. For the connections on the battery posts the lead oxide builds resistance the thicker it becomes. You have to scrap away the oxide coating until fresh clean metal is exposed again on the connector and the post.

There is relay for the headlights under the dash which goes bonkers every 5-8 years for me. My second one just failed last month. Rather than replace it with the original $35 metal cannister 20 amp type I'm going with a $9 new Hella 40 amp one. BTW, Ken Gray at DBE has written a technical article titled 'Lotus Electrics' that supplements the manuals' shortcomings. The first subject on the first page is called 'So What's the Culprit?, a slow or intermittant motor (e.g, starter, window, headlamp lift)'. You might be wise to get a copy. It was free when I paid for the $9 relay.

Oh, I made up my own battery cables from an arc-welder supply vendor. The stuff that can handle 500 amps DC continuously. The ground cable is bolted to the engine via the the lower starter bolt and goes straight to the battery. It's best to avoid any grounding loops anywhere.