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Let There Be Headlights!

May 24th, 2010

Believe it or not, I got my wife to ride in the truck last night!  I lured her with ice cream – but still.  Now that the truck is running (reasonably) well, I’m wanting to take it out more often so an ice cream run seemed like a good start.  After we had finished our Marble Slab goodness, we headed home.  It was probably 15 minutes or so after sunset, so as the heavens went out, I flipped the headlights on.  Now, they have always been a bit dim.  And they had a bad habit of flickering every once in a while that I had chalked up to a loose connection.  Recently I took the connectors apart, cleaned them up, and slapped some bulb grease on them in an attempt to rectify that.  But it turns out I was mistaken – that was not the problem.  Or at least it wasn’t the WHOLE problem, because after the headlights had been on for ten minutes or so, they started flickering again.  And not just a little flicker.  Imagine a signal lamp operator with turrets and you’ll get the idea.

I discovered after some (frantic) experimentation that if I turned the lights out for a minute or so, I could get a few minutes of non-blinking headlight.  But we were ten minutes or so from home – and I’m pretty sure the people around us thought I was trying to tell them to pull over.  So I pulled over and did a bit more experimentation.  I discovered that if I unplugged one of the lights, the other would operate flicker-free.  so we went the rest of the way home as a popeye.

Some research led me to believe that the problem lay in the wiring.  A common upgrade for old C/K trucks is a “Headlight Relay Upgrade”.  The OEM system routes power from the battery, through the fuse box, through the headlight switch in the dash, through many feet of wire, to the driver side light, through several more feet of wire and finally to the passenger side light.  That is a lot of room for resistance.  This resistance can eventually cause the switch to overload, hence the blinking.  It also results in dimmer lights, as they aren’t getting the voltage they really need.  The solution is to take the lights out of the circuit and instead have the power from the switches activate two relays (one for low beams and one for high).  then you can run higher gauge wire directly from the electrical system, through the relays and into the lights.  Much less resistance.  If you Google it you’ll get a ton of pages on it, but my favorite, and the one I used is here. Really helpful info.  I ended up using  Optronics A715 relays – less than four bucks a pop at O’Reilly’s.  I used 10 gauge wire for most of it which was overkill and a bitch to solder, but it was what I had on hand.  At least in the future if I want to add HIDs or something I won’t have to run new wire.

It took about four hours or so, but the result is working headlights.  They do seem brighter too, so bonus.  Another problem taken care of!

The big problems left now are:

  1. Paying someone to replace the oil pan and gasket
  2. Replacing the transmission pan and gasket
  3. Getting the carb adjusted or rebuilt
  4. Replacing the rust tank and lines
  5. Rebuilding the rearend
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