another headlight problem

[sdgarman]

Hi, the headlights stopped working, main beam light on the dash board is on all the time when you switch the lights on and full beam will work when pulling back on the stalk, have changed the bulbs and checked fuses, the headlight relay doesn't appear to be in the main engine fuse box so not sure where to find it, any help please.

[HONEST AL]

Headlight woes

Shaun,how do.Couple of weeks back I was in the process of fitting bigger bulbs to two of my spots,which are controlled by the main beam,the current to trigger the relay being taken just to the rear of one headlight bulb.When I switched them on both headlights "blinked off"one at a time,and there seemed to be no current at the spots.Much scratching of head,checked the fuses and all seemed ok,so decided to look for the relays,took me ages but found them,along with some other fuses in an oblong box attached to the inner wing on the drivers side.Inside this box are several relays and about 10 fuses,two of which seem to control the headlights,utilising the relays.I took the two fuses out and checked them,all seemed okay but to be on the safe side I put two new ones in and the headlights worked.I am not sure why,but can only assume that the alloy of the fuse blade built up a bit of oxidisation and the caused a resistance in the circuit and this stopped the relay operating correctly.I then relocated the trigger wire take off point to just under the steering column where all the switches are,no problems so far.
Is it possible that the relays on your truck are stuck in the "on" position for main beam,if there is some resistance in the circuit the relay could be sparking across the terminals ,the points of contact can become very pitted over time and they are around 15 years old.If you are very careful,take the relays out and open them up,you might just be able to file down any problem areas on the contact faces and see if that cures your problem,or just fit new fuses and relays,cant be too expensive.I am always quick to point out that I am no expert,but I think the wiring in these trucks is very sensitive to voltage drops,hence the slowness of some window motors,sometimes just removing a fuse or relay and then refitting it clears the problem,give it a go and let us know how you get on,Alan

[sdgarman]

Thanks for the reply Alan, my thoughts were the same as yours, relay has been checked and is working the fuses are all fine, been through most of the area with a meter and still nothing, i think its starting to look like the column switch, the puzzling bit is the high beam light on the dashboard on all the time the main lights are turned on, i will post any updates.