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my rebuilt headlight motors are not getting enough voltage to travel through. I have fought the old wiring long enough-I know the motors are ok, as I had them opening in about a 15 count with much finagling of the wiring a year ago. The ground at the header is good.
I have cleaned my rollover switch which looked ok anyway as of this morning and decided to try and up the voltage by wiring the relays as others have done. Plan is to us the rollover as a "momentary ground" for each relay. Scratching my head on best place to power the low voltage/switch side of the relays. Thinking about the ignition coil of the ballast resistor doesn't get in the way.
Anyway, can you guys critique this photo? Biggest question is underhood source of the switched power. I know the horn relay will provide big voltage for the motors.
Thank you in advance- could not search and find the old threads I remember on this. Phone causing typos.
Last edited by ChattanoogaJSB; 09-26-2016 at 12:57 PM.
The horn relay buss is a good idea, you'll still want some sort of fuse/circuit breaker in that hi-current line off the horn buss to replace the one the headlight motors use that's above the DS kick-panel. A 30 amp ATC, blade type fuse could be used or you could just move the original circuit breaker.
If your using your dash headlight motor switch as a ground trigger to activate the relays, then, your lo-current relay power could still be off the horn buss.
Its a good idea to avoid the ignition circuit to power anything...voltage spikes can get introduced and cause hard-to-troubleshoot issues; if you've converted from points to electronic then its even worse. Besides the headlight motors weren't switched power originally, they worked with the ignition off.
Last edited by Frankie the Fink; 09-26-2016 at 01:11 PM.
The horn relay buss is a good idea, you'll still want some sort of fuse/circuit breaker in that hi-current line to replace the one the headlight motors use that's above the DS kick-panel. If your using your dash headlight motor switch as a ground trigger to activate the relays, then, your lo-current relay power could still be off the horn buss.
1) yes Frankie I agree definitely a 30a inline blade fuse from horn relay to the "big voltage "30" post on the relays- replaces the protection from circuit breaker.
2) so you're saying use the same horn relay terminal to power the "switching" side of the relay?
Does the existing circuit obtain it's voltage from the ignition coil?????? That would be the last place I would draw current from (I assume you have a ballast resistor feeding the coil. which will drop the output voltage substantially - to any higher current devices).
I don't have a C2, so ignore my ignorance.
Plasticman
yes the resistor was a big red flag to me too. I am just trying pull the switching voltage from a good place.
I see no reason not to run both hi-current (properly fused, motor power) and lo-current (relay power) wires off the horn buss.
Simplifies things, keeps the wiring much cleaner and the ignition circuitry is unaffected. If you mount the relays along the radiator core support (as I've seen done) you will have a very clean installation with short runs for the power wires.
If you get real ambitious you could put the headlights themselves on relays at the same time.
Last edited by Frankie the Fink; 09-26-2016 at 01:16 PM.
He wants to use the rollover switch to ground the relays, not to power them.
Yes. I knew that at the outset it'll work as well as a power lead trigger...
For that matter, why doesn't he just replace all of his wiring to get full power to the motors ? I'm just trying to help the guy along with his chosen solution...and his specific question... Not offer my own.
Last edited by Frankie the Fink; 09-26-2016 at 02:21 PM.
Yes, I realize a dash, engine, and light harness are all good things. I'm not trying to be overly cheap, it's just that everything else is working fine- and I've read others posts about being pleased with relays.
To conclude this post for future searches the relays work great! My rollover switch now works as a momentary ground, the master to which is on my steering column bracket.
Also unforeseen is the power to the motors at the "30" post on the relay works fine and has the 30 amp fuse in line. The power for the switching of the relay cannot come from that source- with much head scratching I tried a jumper to the battery which made "all well."
I still have some cleaning up of the wiring and mounting and I may try and take the switch power from the alternator lug.
All i can conjecture about the horn relay power is that it is already grounded (?) and powering both relays all the time.
That's great. I see no electrical reason that the relay power can't come from the horn. It's a main feed for power.
i also see no reason the switching side of the relay could not be shared with the same lead from the horn relay that powers the "big" 30 marked pole- but when it was hooked up in this manner there was full voltage on the GROUND post of the relay which was wired to my rollover switch. And that was with the rollover grounds open (no pressure on switch). Splitting off the power fixed it.
I may post post all this on the "electrical" part of the forum for my own edification.
Whatever works.
The relay trigger power just activates the coil wire on the armature to pull the contacts in...a very low resistance circuit, so you may well have read electronic voltage potential across it...
And...not all relays are the same...they are different types of the same design...where the internals are different. Some have resistors...some ahve diodes and some have neither.
The schematic usually printed on the top of the housing of the relay will show if it has a diode, resistor or nothing.
For those who care to possibly fill in some holes in their electrical knowledge...this may help.
09-26-2016, 12:54 PM
Headlight motor relay wiring diagram opinions
