Headlamps- part 2

I should say something more about pod removal.
Its pretty well straight forward but a better way to remove the connecting rod is to do so at the bottom. This joint is referred to as a "ball joint" but on these early cars its not actually a ball joint  at all- In fact this is a screw on yoke-eyebolt which pivots on a shaft from the motor actuating arm. Best procedure is to reach into the pod and unscrew the retaining nut and washer before pulling the eye bolt off the motor shaft. This allows the pod to be moved easily and indeed removed when the mounting bolts are taken out. What's even better is that this doesn't affect the adjustment at all when its refitted! To refit I found it easiest to attach the actuating rod back onto the motor lever and then wind the motors up or down by hand until the pod and bonnet bobbins coincided- it was then easy to screw the bolts through.

Adjustment yoke bolt on motor actuating rod. Best to make sure this is clean and greased and so turns easily to make adjustment easier.

Also I found that the nut on top of one of the connecting rods had stripped so I will retap this and fit a new nut, but if you can avoid it, don't remove this nut as refitting is a bit fiddly owing to the spring tension..

Headlamps Part 2

Having removed the pods the motors will easily follow, they are held onto the mounting bracket by 3 small bolts (10mm) and washers. Support the motor as you remove the bolts, its surprisingly heavy. I don't pretend to have understood the action of the headlight pods which owes much to the dark arts. Lotus need several pages of wiring diagrams to explain and I will not reproduce those here but try to read this text in conjunction with these pages and maybe it will help. Here is my best analysis.

Wiring diagram pod motors- G- green, N brown, U-blue, B -black

Firstly the power feed to the motors is not affected by the the column switch - it doesn't even pass through the lighting switch. However when the pods are not moving this motor feed is interrupted by the relays (one for each headlamp). The lighting switch actually controls the switching current to the relays which in turn connect or interrupt the power feed to the motors. However its not a case of "on" or "off" because power is also always applied to the switching circuit, but this  circuit is in its turn interrupted by the two micro-switches in the motors themselves (one for "pods up" and one for "pods down"). This means that when the pods are still in either up or down position, the switching current to the relays is broken by the micro-switches, relays remain open, interrupting power feed to the motors.   In this open state the relays actually earth the motors to prevent or control any possible movements when not required. The final complication is that despite the terms "up" and "down" for the micro-switches in the motor, the motor actually turns in the same direction all the time. It simply rotates between two fixed positions which are set by the micro-switches which interrupt the relay switching circuit when the motors reach the next set position. - So far so  clear? Well maybe not, and I still can't get my head around the flash circuit and how the lights are actually turned on but its a useful approximation.

If we think about one pod motor only, then there are 5 wires that go into it, 3 are routed through a multi-connector and  2 join via individual connectors. In my wiring diagram the left and right headlight motors are shown with different colours, but in the actual car both sides were wired the same and both used the scheme shown for the right headlight motor so I will use these colours in this description. The two individual wires take power from the lighting switch to the two micro-switches in the motors.  One of these wires (Brown/green) is live when the column switch is "off", and the other (blue green) is powered when the  column switch is "on".  Although there are two micro-switches, they are actually joined together by a copper strip that functions a little like a see-saw.

Cover removed from motor to show microswitch and individual wire feeds that supply contacts at each end of the copper strip. White nylon plugs are invisible beneath the copper strip.

 The two feed wires above supply contacts at each end and when the see-saw touches down at that end then power flows up the seat of the see-saw  and out through the pivot point where a green wire is attached. This wire is the centre wire in the three plug multi-connector and takes the power into the relay circuit. No matter which direction the pods are travelling their motor relays are always fed via this green wire, what changes is the end of the seesaw from which the green wire is receiving its power. In our example when the pods are down then the seesaw is tilted towards the "up" microswitch closing contacts at that end and breaking contact at the other. Operating the column switch then connects power to the blue/green wire connected to the ""up" microswitch. Since this switch is closed power can then flow up the seesaw and out via the green wire to the motor relays  (one after the other). This causes them to close and so connect the power (via the black/green wire in the multiconnector). Power flows through the motors causing them to turn and then out to earth via the remaining wire in the 3-prong plug, the black earth wire.
The motors then begin to cycle, and as they turn, gearing within them raises or lowers two plastic plugs which push on the arms of the see saw. As the pods rise the plug on the side of the "up" switch starts to rise whilst that on the opposite side starts to retract. Just as the pods reach fully "up" the plastic plug has risen sufficiently to push up that side of the see-saw and  break contact at the "up" micro-switch. This interrupts power supply to the relays which therefore spring open again cutting power to the motors and thus stopping them with the pods in the "up" position and headlamps on. In fact when these relays open they actually earth the motors so that movement is stopped immediately.
Just as contact at the up micro-switch  has been broken by the rising of that plug, the retraction of the plug at the opposite end has allowed the see-saw to sink, closing the contacts at the "down" end. Whilst the column switch remains in the "on" position there is no power feed through this contact, but this changes when the lights are switched off. This action then sends power  to the "down" microswitch which can then  run up the see-saw and out via green wire to close the relays and start the motors turning again. This action will then lower the pods whilst the geared movement in the motor raises the plastic plug on the "down" side of the see-saw until this breaks contact between the see-saw and the "down" switch, restoring contact at the "up" switch. Once more when contact at the "down" switch is interrupted, the relay current collapses and power to the pod motors is cut, stopping the pods in their newly lowered position. I think the switch must be arranged such that both switches are actually connected during pod transit (either up or down) because this is a requirement for the flash circuit (see below). Also if it were not so then turning the switch off during pod up movement would cause the pod to freeze in a partially open position

This then is my understanding and lead me to the following test procedure. My Sealey PP1 probe has now been delivered... and its fantastic- just right for this protocol and given the potential for the legion of electrical faults possible in any Lotus, I would suggest that this or something similar is essential kit for any Lotus owner!- No I'm not on any profit sharing scheme!

1. Check relays. Test or replace all relays with known good ones. If you can't do that try changing them over- if only one pod is affected does the fault switch sides if you switch relays? Trace the wiring though to identify the relays- mine were arranged in a different order from that shown in the manual.

Relay pin designation

Testing is relatively simple. Place the relay  upside down and orientate it with the single edge-on contact (30) towards you at the front. Connect a conductivity meter between this contact and the centre contact (87a) it should read connection. Test between the front and the rear contact (87) in this centre row- there should be no connection. Apply 12v between the side contacts (85 and 86), the polarity doesn't really matter. Listen for an audible "click" and check that contact has now been made between front (30) and rear (87),  and broken between front (30) and centre (87a). If all checks out the relay is good, but even so make sure the pins are clean and rust free and do your best to clean the relay mounting block slots too-if anyone knows a good way to do this, I'd appreciate the heads-up!
2. Check motor. Disconnect  all the wires from the motor, apply 12v between the black/green (+ve) and the black earth (-ve) wires at the three pin connector going into the motor (take care not to short the supply wires). The motor should turn continuously, if not then the fault lies in the motor itself.
3. Check microswitches. Reconnect the three wire multiplug, look at the motor and see if the arm is in the raised or lowered position and thus in which direction the next movement should be. If its not  close to either of these positions turn it using the hand knob until it is. Apply 12V (+ve) to one of the single wires entering the motor (ie if arm is "up" apply feed to the "down" microswitch and vice versa). The motor should then turn until the microswitch breaks contact, e.g in this example the arm should move down and stop.   Then apply power to the other wire and check that the motor cycles back to its original position.  If movement is not achieved in the expected alternating pattern suspect the microswitch.

Flash relay

I cant fully get my head around this, but the flash relay is always connected somewhere. When the column flash switch is in its down position the flash relay  is in its open (unpowered) position and connects power to the "down" micro-switch circuit ensuring pods are lowered. When the column flash switch is operated it applies 12v across the flash relay to earth, causing the contacts to close. When these contacts close they disconnect the down circuit and connect the power to the Blue/green up micro-switch circuit raising the headlamps using the same current path as above. When the flash switch is released the flash relay springs back to energise the "pods down" circuit and the pods will lower.

The micro-switch presumably contains some cunning timing gears to ensure that both up and down contacts are actually in connection whilst the pods are being raised. This means that the "down" circuit always has access to the down micro-switch during "up" movement since if it did not, releasing the flash switch whilst pods were only partially raised (and thus energising the down circuit) would result in their freezing in this position. In other words (and here's where the see-saw analogy breaks down) the see-saw must be flat for most of the time that the pods are actually in motion.

Well that's my understanding anyway- I'm sure someone will point out my errors but at least it led me to a sensible testing procedure and located the fault.
In my case applying power to the motor showed that both could turn perfectly well. Applying power through the micro-switches showed that although the right motor responded to both, the left didn't respond to the "up" signal. I suspected a dirty micro-switch contact but cleaning gave no improvement. It was eventually tracked down to the nylon pegs that raise or lower the see-saw contact strip. One of these seems to have got some dirt on it meaning that it was too high and even when fully retracted, it did not allow the micro-switch to make contact! I cleaned the head of the nylon rod and all was well.**

I have since found that this rocker is the weakest point invthe system and most faults are due to dirt ir damage to the copper strip. Many can be repaired simply by cleaning or rebending the strip. However it is hard to bend the strip down whilst its in position and to get around this you can release it by carefully drilling iut the central rivet. Its easy to shape and clean it once its off and it can be refitted using a 6 ba screw and nut thriugh the rivet hole. Have the nut facing upwards where there is plenty if if room but you may need to reduce the moulded plastic boss on the underside to allow the screw head to sit high enough that it doesnt obstruct the rotation of the triggering system underneath.

I re fitted the pods and tested again- I had to lower one pod by hand so perhaps there is some sort of starting coordination position (?) but after that initial hiccough the pods and headlights are operating fine. Strangely I seem to have lost  horn function but I will try to track that down later. One last thing is that I noticed that on turning on the lights the pods seem to lower a little before they start to rise and I'm not sure why this should be- for the time being I will assume that this is normal behaviour!!!

Note added later...
Having checked the various forums on line I think the conclusion is that this lower-to-rise behaviour is common, although I still suspect there is an adjustment somewhere that could eliminate it. I also found this excellent account of how to service the motors on lotusexcel.net. Its written by member "fueltheburn" so I'm not claiming any copyright or originality- just passing on some excellent advice that I appreciated at the time.