Low Beam Headlight Relay Mod for late fuse box X1/9 85-88

[kmead]

This is a tutorial to improve low beam light output and reduce the load on the light switch, column switch and the ignition switch by adding a relay to supply power to fuses 3 and 4 with minimal wiring changes or additions. This modification will compliment the existing high beam relay which feeds fuses 5 and 6 on a late fuse box.

This is a first draft and any suggestions to improve, make clear or other changes are welcome. The next version will cover using the unused AC relay blocks to further reduce the amount of new wiring needed (hopefully adding just a new power supply wire if desired and moving three existing wires).

I will be doing several other tutorials similar to this for a starter relay, ignition switch load reduction relays, wiper relays, and electric window relays. Any suggestions on format, descriptions etc will be integrated into those tutorials. I will also look at doing similar tutorials for earlier cars but will need someone who has an earlier car to verify wire colors and locations along with some pics from them.

I hope this helps others besides being one of my mental gymnastic pastimes as I look at wiring diagrams

 

[Dr.Jeff]

I've only skimmed through it for now, but it looks like a excellent job. Thanks for taking the time to document this and any future projects of this nature.

If you had asked for a earlier fuse box example a couple months ago, I completely rewired my '79 and could have supplied all of the needed info. But it is done now and no longer stock so it won't be of any help.

If the car has the AC wiring and you want to reuse the AC relay for the headlights (i.e. the AC system has been removed), then the power feed is already good for the AC relay....it has a beefy lead to it. So only a couple of wires will need to be moved to get the right trigger signal to that relay.

 

[JKIDD]

I believe I have a 79 fusebox assy with the torpedo fuses I cut out out of 1 of the organ donors I had. Is this what you're looking for?

 

[kmead]

I believe I have a 79 fusebox assy with the torpedo fuses I cut out out of 1 of the organ donors I had. Is this what you're looking for?

I've only skimmed through it for now, but it looks like a excellent job. Thanks for taking the time to document this and any future projects of this nature.

If you had asked for a earlier fuse box example a couple months ago, I completely rewired my '79 and could have supplied all of the needed info. But it is done now and no longer stock so it won't be of any help.

If the car has the AC wiring and you want to reuse the AC relay for the headlights (i.e. the AC system has been removed), then the power feed is already good for the AC relay....it has a beefy lead to it. So only a couple of wires will need to be moved to get the right trigger signal to that relay.

Thank you. I haven’t poked into the AC stuff too much so I will go and have a look at what the supply is and where it comes from. I am working on changing my supply to all the ignition switched circuits and will look at the circuits for AC at the same time.

Yes, in looking at the arrangement of the systems, a very similar solution will work for the pre 85 FI and carb cars going back to at least ‘76. They all use a similar arrangement and it would be easy to just add a relay for the low beams and a relay for the high beams assuming your general wiring is in good condition. I will do some research and post up any needs I may have.

 

[JKIDD]

I may also have 1 for the 81 FI car as well. Let me know if I need to start digging...

 

[kmead]

I may also have 1 for the 81 FI car as well. Let me know if I need to start digging...

At the moment, no. I need to do the second half of this one. I may not need much in the way of pics, perhaps some verification in the future. Thank you, greatly appreciated.

 

[Cratecruncher]

I just saw this Karl. Great work. A mod even I admit is sorely needed!

 

[Roxyred]

Hey Karl, would this be the plan for me to upgrade my standard sealed beams to LED for better vision?

I'm going to save this and give it a good look over, I've been meaning to do research on how to do this upgrade to my X's. I have one on my spider already, sooooo nice to be able to see at night.

 

[kmead]

LEDs should require less power so one may not need this upgrade. However it is still an easy way to take some load off the various switches.

if your X doesn’t have AC I will be doing an additional few pages to add on how to use some of the existing empty relay sockets. It will be less work but a few more wire substitutions.