Head lamp lift motors

[Carld21]

After weeks of trying Ive finally figured out the wireing on my lift motor, and just wondering if anybody had a similar problem. The loom S1 with the 3 pin switch, The motor are the later S3 which have a totally different connections I belive they used TR7 motors. with a 5 pin switch.

Will I need a 5 pin switch to enable me to make the light go down or can it be done with the 3 pin switch. I think i know the answer but i thought i'd ask. Thanks

[USAndretti42]

If you still have the limit switches, you may be OK or you could convert it to the S2 set-up. The extra connections are for the changeover relay which is a normal relay which uses the normally-closed contact to lower the lamps and the normally-open to raise them. On the front of the motor, where the drive spindle is, is a worm and gear. The motor spins the worm which turns the gear to which is attached the spindle. On the back of the gear is a lump. As the gear rotates the lump pushes nylon pegs. These, in turn, poke through a wall in the gear housing wher there is a copper strip and three terminals. On connects to the centre of the strip and goes to the motor relay. There is also one contact at the each end of the strip so that the strip lies on them to make the circuit. The pegs push up one or other end of the strip depending on whether the lamps were up or down.

To get the headlamps up, the changeover relay is energized by the headlamp switch so power is applied to the normally-opoen contact. This is connected to the contact which has the strip resting on it, then along the strip to energize the motor relay. When the headlamp is up, the lump pushes that end of the strip away from the contact and the motor stops. Turn off the lights and the changeover relay is de-energized so the normally-closed pin feeds power to the contact at the other end of the stip. As the lump is at the other end of its rotation, this is has the strip against so the power goes along the strip to the centre contact again and to the motor relay to drive the lamps down. It continues until the gear rotates and the lump pushes up the peg at the other end of the copper strip to break the circuit. Diodes in the wires to the ends of the strip prevent things getting confused when both end of the strip are in touching their respective contacts.

The proble you may have in doing this is that you cannot adjust easily the degrees of rotation needed to raise or lower the lamps as the lump is part of the plastic gear in the front of the motor.

[Carld21]

Thanks for your help on both topics