Upgrade your headlight relay to electronic, How to wire up the new relay Options

[Mike Bellis]

The factory highbeam relay is a mechanical toggle relay. As they get old, they stop working correctly. It takes multiple pulls on the colum switch to engage the highbeams. Some may stop working completely.

Below you will see how to wire up an electronic relay. It's very easy to do. The very smart European builders have standardized their relay terminals. So many manufaturers relays will work. The picture below is a Saab relay. This relay can be found for $5-10 at junk yards. The 914 relay is about $50





You will need to jumper terminals 30 and 86 together with the 914 wire from terminal 30

Terminal 56a will go to the 914 Yellow headlamp wire

Terminal 56b will go to the 914 White headlamp wire

Terminal S will go to the 914 wire from Terminal S

The final wire will be a new Ground wire you will add to terminal 31

That's it! You will now have an electronic highbeam relay. Now you have to figure out how to mount it.

[SirAndy]

(IMG:style_emoticons/default/thumb3d.gif)
I've been thinking about doing that for a while.

There's a lot of cool stuff available these days that wasn't even around 10 years ago. Let alone 40 years ago.

(IMG:style_emoticons/default/driving.gif) Andy

[pbanders]

Very cool, thanks! BTW, most OEM headlight relays can be revived by opening them up and doing a bit of clean-up. Mine is 40+ years old and still working.

[Mike Bellis]

Very cool, thanks! BTW, most OEM headlight relays can be revived by opening them up and doing a bit of clean-up. Mine is 40+ years old and still working.

I tried that on mine first. The spring had formed a memory and always landed the internal cam on the low beams. Once this happens... It's over.

The electronic type works every time.

[76-914]

Good info. Could this be added to our classic thread forum. I'll be able to look it up later when I need it. Thx for the tip.

[Mike Bellis]

Good info. Could this be added to our classic thread forum. I'll be able to look it up later when I need it. Thx for the tip.

I dunno...

Andy? Make it so...? (IMG:style_emoticons/default/type.gif)

[stephenaki]

I just may have to do this as I think meine relay ist kaput! Can't seem to get the high beams to come on. (IMG:style_emoticons/default/dry.gif)

[jim_hoyland]

Is the original high / low relay square ? Can't picture it--

[Krank]

If this circut is just used for the dimmer circut then I believe you could just use a brand new switching relay to achieve the same results. They run about 10.00 to 15.00 I don't have the 914 schematics so I can't tell you which wire goes where but the relay used in the above example (it is a mechanical one also btw) utilizes one power source and switches it from one output to the other. You can also then use a brand new base connector to make everything look neat and tidy. If someone would send me the schematics of the lighting system I could make a lighting schematic with the new relays.

HELLA relays and bases
http://www.hella.co.nz/?m=search&f=rel...6&B1=SEARCH
(bottom two relays)
Note: use the 40amp circut for the hi beam (pin 87)

A note on using diode relays with sensitive electronic equipment like fancy disc players
http://www.hella.co.nz/?t=9&pcid=251

They do list a solid state relay but not a switching one

You can even use a delay relay to have a fancy courtesy lighting system so your lights stay on for a short interval after you turn your car/lights off.

I used two switching relays to replace the power window system in my '68 Lincoln Continental. The polarity needs to be reversed to operate a DC motor in the other direction. I also used a switching relay to supply power to my road lights on my pick-up only when my high beams are on so that I can dim my high beams and turn off my road lights with one click rather than fumbling around for another switch as a car approaches. Relays are fun! (IMG:style_emoticons/default/biggrin.gif)

[SirAndy]

I'll be able to look it up later when I need it.

Or, you could just bookmark this thread ...

(IMG:style_emoticons/default/rolleyes.gif) Andy

[Mike Bellis]

If this circut is just used for the dimmer circut then I believe you could just use a brand new switching relay to achieve the same results. They run about 10.00 to 15.00 I don't have the 914 schematics so I can't tell you which wire goes where but the relay used in the above example (it is a mechanical one also btw) utilizes one power source and switches it from one output to the other. You can also then use a brand new base connector to make everything look neat and tidy. If someone would send me the schematics of the lighting system I could make a lighting schematic with the new relays.

HELLA relays and bases
http://www.hella.co.nz/?m=search&f=rel...6&B1=SEARCH
(bottom two relays)
Note: use the 40amp circut for the hi beam (pin 87)

A note on using diode relays with sensitive electronic equipment like fancy disc players
http://www.hella.co.nz/?t=9&pcid=251

They do list a solid state relay but not a switching one

You can even use a delay relay to have a fancy courtesy lighting system so your lights stay on for a short interval after you turn your car/lights off.

I used two switching relays to replace the power window system in my '68 Lincoln Continental. The polarity needs to be reversed to operate a DC motor in the other direction. I also used a switching relay to supply power to my road lights on my pick-up only when my high beams are on so that I can dim my high beams and turn off my road lights with one click rather than fumbling around for another switch as a car approaches. Relays are fun! (IMG:style_emoticons/default/biggrin.gif)

Those relays are standard SPDT (Single Pole Dual Throw) relays. They will not work for the dimmer. the 914 and most other cars send out a ground pulse every time you pull the lever. It does not latch on or off. You could build a latching relay setup with 2 or 3 SPDT relays and use the ground pulse to trigger it. Way more difficult.

The Saab relay and the like use an electronic circuit to hold the latch on or off. On the Saab relay terminal 86 is the switched power from the key and terminal 30 is the power from the lighting circuit. Since the 914 lighting power is controlled by the key, these two terminals jump together. Terminal 31 is a ground for the electronic circuit.

On the 914 relay terminal 30 is the light power AND the positive for the coil. The S terminal is the momentary ground for the coil. When the coil is grounded, the relay pulls in and toggles a cam inside the relay. when the relay de-energizes the cam drops on a mechanical tab that directs the cam right or left. It is designed to toggle right then left then right again every time you pull the lever. Over time the centering spring on the cam will develope a memory to the right or left. this causes the cam not to toggle to the other side of the tab. Hence the cam will always land on the high OR low side contact and never switch over.

I think the bottom line is this. You can make it work with multiple SPDT relays and build a latch circuit. A single replacement relay is a cleaner install and more reliable.

[tracks914]

Or you could just drive it on sunny days!!!

[76-914]

I'll be able to look it up later when I need it.

Or, you could just bookmark this thread ...

(IMG:style_emoticons/default/rolleyes.gif) Andy

Good tip Andy. I just bookmarked this. But what about future members that don't know of this post? (IMG:style_emoticons/default/idea.gif)

[jim_hoyland]

Where is the replacement unit mounted ?

[IronHillRestorations]

This is good stuff Mike!

[Mike Bellis]

Where is the replacement unit mounted ?

You will need to get a little creative here... Zip tie, velcro, double sided tape.... If you are really creative, cut the mounting tab off you old relay and JB weld it to the new one. Or use an old round relay base, cut the rubber mounting surface off it and glue it to the new relay. How about bending a strip of metal to strap it down with screws.

Honestly, I just shoved mine above the fuse panel with a zip tie.

[siverson]

So this Saab relay is just used to replace the switch between high and low beam. That is, it doesn't provide a new power source to pull from for high wattage bulbs. Is that right?

So I could use this Saab relay to have an electronic toggle, but it's still a good idea to have a relay and new, larger diameter wire that is separately fused on the outbound side of things if high wattage bulbs are used.

(I'm cleaning up my headlight wiring as I put my car back together...)

-Steve

[Mike Bellis]

So this Saab relay is just used to replace the switch between high and low beam. That is, it doesn't provide a new power source to pull from for high wattage bulbs. Is that right?

So I could use this Saab relay to have an electronic toggle, but it's still a good idea to have a relay and new, larger diameter wire that is separately fused on the outbound side of things if high wattage bulbs are used.

(I'm cleaning up my headlight wiring as I put my car back together...)

-Steve

I'm not sure what the wattage of the Saab relay is. You are more limited by the wire size than the relay size. The factory wiring is just barely adequate for the stock lights. This is the case for every car, not just the 914. the factory's make the wire harness as cheap as possible.

So It may be a good idea for additional relays and thicker wire. (IMG:style_emoticons/default/smile.gif)

[Cap'n Krusty]

Nice. FYI, the "builders" aren't responsible for the standardization of terminal numbers, the governments in Europe take the credit. The only thing the builders are responsible for is deciding to sell their products in Europe.

The Cap'n

[siverson]

Thanks. I got this working yesterday. Saab relay for switch, plus 8 gauge wire from battery to front trunk, and 3 more standard relays in the front trunk for low beam, high beam, and driving lights.

-Steve