Posted on: November 18, 2015

by David R. Harris in the March 19996 RootesReview

This is a hint that others may want to incorporate into their wiring and the reasons are as follows:

Most drivers today are accustomed (when driving in the dark) to operating their vehicles with better lighting than what is available with ordinary sealed beams. There are new solutions to this problem, to drive with a stick out the window so as to feel the curb or install quartz-halogen headlamps.

The trouble with the stick solution should be fairly obvious, but higher powered headlights present a more subtle problem.

The Lucas switches in British vehicles are fine for the sealed beam systems, but the volt/amp spikes caused by the quartz lights will cause one of the following, the contact will either carbon up or burn, both of which will destroy the switch. This can be overcome by installing a simple relay in the circuit, an easy wiring job that can be accomplished by anyone with a wire cutter, a crimper and a screwdriver.

The first step is to locate the wire that operates the headlights at the switch and move down the circuit a comfortable distance to make a cut in the wire. Make two connections one from the switch to the relay (coil feed) and one from the point side of the relay to the other side of the cut. The final connections are an earth (ground) from the coil of the relay and a full time feed to the pivot of the relay. This feed may be found at the run side of the ignition switch, the control box or even the battery.

I prefer a Bosch heavy duty relay and base for the modification as they can be fit anywhere out of sight and unobtrusive. The other advantage to this relay is that it will outlast any other available. A fuse should be inserted in the full time power feed to the points to prevent a short and melt down.

Ed note: headlight relay kits are available from various sources

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