The Stovebolt Site Forums The Shop Area The Electrical Bay headlight switch faliure ?

guys,
will a faulty headlight switch kill just the headlights, and not the running/tail lights and front running/turn signal lights ?
the fuse is good.

tonight on my way home from a local car show, the gauge lights flickered, then the headlight went out. the gauge lights still work.

im running a newer fuse block from a 1980 pick up truck. about 2 years ago i installed a "new" headlight switch from one of the various vendors like LMC or brothers trucks. im sure it was made in china, so the quality probably isnt that good.

i guess thats where i will start since the fuse is still good.

thanks for any input guys.

leonard

oh yea guys, when i did install the new headlight switch i also had to put in a new turn signal housing, on the steering column, and lately my brake/tail light have been acting up...... would a faulty headlight switch mess with that too ?
thanks

yes, there are 2 thermal overload breakers for headlights only, the springy contact points on each side, that open under excess current conditions and could be malfunctioning if you have original style bulbs or be fried if you've changed to halogens without a relay .... if you're replacing the switch again check NAPA for one from Danchuk, or get one from Danchuk direct, they are the quality you want

the only involvement of the switch in the rear/turn lights is the brake light power comes via the switch

Bill

WOW, thanks bill for the info.
i did upgrade to tri-bar halogen headlights about 2 years ago also, but was told by them that i didnt have to run any relays with them. they probably just said that to get a sale ?
i see on LMC that they have a "heavy duty headlight harness" which the ad says draws power directly from the battery and not the switch. would it be a good idea to get one of those also while im at it ?
thanks for the help.

leonard

oh yea, the switch you linked form danchuck shows a fuse in the switch..... im 99% sure my current switch dont have a fuse on it.... will buying that switch be better for me ?

leonard

Don't forget to check out the dimmer switch before you change the headlight switch. It's inline between the headlight switch and the lights, and they're bad about developing shorts or open circuits.
Jerry

Len - that small fuse is for the dash lights only, but it should be there ... not sure what the 'heavy duty light harness' would be other than having a built in relay, but the relay is a good idea with halogens, see fifthave electrical here [our knowledgeable moderator!]

and as Jerry says, it'd be worth checking the dimmer sw as well, which might also not like the extra load of halogens

Bill

wow, thanks jerry and bill.... now that jerry talks about the dimmer switch, i remember when i first bought the truck i tried the hig beams and it only killed the lights, so i pressed it again and the low beams came back on. i have never hit the dimmer switch since then, but maybe it has finally went south. is there a way to check the dimmer switch first without having to buy one, like jumping a wire from it or something ? i would hate to buy a headlight switch and it be the dimmer.

thanks so much guys for your knowledge.

leonard

thats a good article on the relay from fifth ave..
how do you hook a relay inline ? is it one relay for both lights or one for each ? looks like a 3 prong setup, and not sure how they would hook up ?

thanks again for the help guys.

leonard

Some of the dimmers have a 3-prong plug with blade terminals on the switch. Others just have three screw-terminal connectors. Find the wire that's hot when the headlight switch is turned on by using a test light or a voltmeter, then connect a jumper from that wire to each of the other wires one at a time. You should get high and low beam lights as you swap the jumper. If none of the wires at the dimmer are hot with the switch on, you need to backtrack to the headlight switch and check it out.
Jerry

relay setup info - another writeup

Bill

wow. you guys are the best... thanks so much for the help.
i went to NAPA today to get some relays, but the guy didnt knwo which one i would need. he brought out a 5 plugged relay and said they come with no wiring diagram and didnt know much about it.
i will search one of the vendors and get what i need early next week along with a new headlight and dimmer switch. i like to do it all at once so i have peace of mind.
its too nice of weather here in south florida to tear into it while the suns up. will wait until later sunday or during the week.

leonard

Try an Ebay search for "Bosch relay". There are at least 500 of them available on any particular day, and just about all of them have a schematic diagram right on the side of the relay. There are multi-pin plugs there for them, also.
Jerry

im a little confused.
on most of the wiring diagrams online they show a 4 wire relay, one in from headlight switch, one for ground, one in from a fused 12v power source and one out for the headlight.

but searching online for relays they all say they are a 5 wire relay.
what would the 5th wire be used for ?
i admit i dont know anything about electrical, other than red is usually hot and black is ground. LOL.

i would like to get the two relays from somewhere here locally. i seen writeups on the radio shack spst 30a relays and they mostly all said they were junk.

any thoughts on where i can get the relays at a local auto supply store like autozone, and what would i ask for ?
could i just use relays from, say, a 1980's truck or car ?

im lost... but you guys are helping me along so im learning.

thanks

leonard

what are your thoughts on these ?

http://www.autozone.com/autozone/ac...mIdentifier=203873&_requestid=986621

http://www.autozone.com/autozone/ac...mIdentifier=946044&_requestid=986685

http://www.amazon.com/HELLA-003510087-Mini-Relay-Bracket/dp/B000VUAJIM

this might help - I believe any of the relays you find will use the same numbering as shown .... the 5th pin would be unused in your application [87A - "normally closed"]

Bill

The 5-pin relays have a "normally closed" contact that allows the relay to power two items, one when it's energized, and one when it's released. Just ignore the "normally closed" contact when you're wiring the headlights. If you've got a 5-wire plug, just clip the 5th. wire off even with the plug to keep it from shorting out, and fill the hole in the plug for that wire with RTV gasket sealer if you choose.
Jerry

thanks for the tip jerry....

just getting back in from trying to diagnose it... i am now more stumped then before starting... here is what i found.

first i checked the dimmer switch for power on any of the 3 terminals, i have no pwer at any of the three terminals.
. here is the dimmer switch.

[IMG]http://i251.photobucket.com/albums/gg307/RATRODKING/1957%203100/DSC04527.jpg[/IMG]

so, i pulled the headlight switch, here are the pics of it, with no little fuse like the one pictured in the pics of the various vendors.

[IMG]http://i251.photobucket.com/albums/gg307/RATRODKING/1957%203100/DSC04529.jpg[/IMG]

[IMG]http://i251.photobucket.com/albums/gg307/RATRODKING/1957%203100/DSC04530.jpg[/IMG]

[IMG]http://i251.photobucket.com/albums/gg307/RATRODKING/1957%203100/DSC04531.jpg[/IMG]

[IMG]http://i251.photobucket.com/albums/gg307/RATRODKING/1957%203100/DSC04532.jpg[/IMG]

when i pulled the switch to the on position, i have power output at ALL terminals... so, does this mean that my headlight switch is good, right ?

why, if i have output at all terminals on the headlight switch, why dont i have any power to the dimmer switch ?
and since there is no power to the dimmer switch, that means there will be no power going out to the headlights, right ?

i pulled the left front headlight and here is a pic of the 3 pronged terminal.

[IMG]http://i251.photobucket.com/albums/gg307/RATRODKING/1957%203100/DSC04533.jpg[/IMG]

obviously, there is no power to any leg of the terminal.

i do have running lights, blinkers, and front running/turn lights... just no headlights.

i checked every fuse in the fuse block and all are good....

could i have fried a wire somewhere ?

i am at a loss now guys.....

thanks in advance for the help again.

i think i have checked everything you wanted me to check....

leonard

yes, you probably have a broken wire or bad connection - you could track the headlight wires from the switch onward with an ohm-meter .... I'd also replace that totally incorrect light switch so you have all the proper connections as per the factory wiring diagram, although it looks like you don't have properly color coded wiring, which would make troubleshooting MUCH easier

Bill

thanks bill...... yea, the fuse block and most of the wiring is from the 1980 chevy truck the previous owner pulled the running gear from....

ok, now here is what i just found.

looking at the dimmer switch, i noticed that there was one wire that was blue with a yellow stripe. i looked at the headlight switch and it had the same wire coming from it, blue with a yellow stripe.
i goes directly from the headlight switch to the dimmer switch, but through a male/female quick disconnect, along with i think 3 more wires..
i was fiddling with it checking for power with my test light, and dint have any power after the male/female connector...
then all of a sudden my headlights were working..... pressed on the dimmer switch and i had high beams..... went inside the truck, push the headlight switch to off, then pulled it back on and didnt have headlights.... checked the blue with yellow striped power wire and didnt have power....
now, with the headlight switch on, i have no headlights, but every single time i poke the test light into the male/female connector that is about half way inline to the dimmer switch, i get headlights, as if the grounding from the test light is making the headlights work...
what the heck is going on here ?

im thinking about running a new power wire from the headlight switch to the dimmer switch... what are your thoughts on that ?

and obviously, even if i get the headlights to work, i am ordering some relays just to be safe...

im learning guys, im learning. LOL.

leonard

well guys i now have headlights !!!!!!!

i ran a new hot wire from the headlight switch to the dimmer switch, and viola... the headlights now work every single time i turn them on...
i am gonna order a new dimmer switch, since it always gave me trouble on the high beams, and also two relays for the ront headlights, and i hopefully will be fine.

i can not thank all of you enough for helping me along with this problem. without this site, and a couple members who help me offline, my truck would not be running...

thanks again guys....

leonard

oh yea guys, and is it normal for the back of the headlight switch to get pretty hot when the headlights are on for a while ?
i had left them on accidentally while putting tools away, went to put the switch back in the dash, and the back part was pretty hot....
if its not normal, would the relays help ?

thanks again guys.

leonard

the switch case can't get hot on an original style switch because of the thermal overload contacts on the outside of the switch, I see your switch doesn't have those - the semi-separate part at the back of yours must be the headlight contacts, no telling if it's protected in any way - I still recommend getting a correct switch, but yes, the object of the relays is to remove the main current load from the switch itself, the only juice thru the switch becomes the small current needed to activate the relay

Bill

bill, thanks for the explanation.
i am gonna order the correct switch, (hoping i can figure out how to hook it up), and a new dimmer switch, along with two relays.

thanks again guys..
leonard

Any switch or connector that gets hot to the touch is a pretty good sign it's overloaded. Once you get the relay system working, the heavy load on the switch and the dimmer will go away.

Some things never change- - - -we were putting relays on headlight systems back in the 1950's to make 'em burn brighter.
Jerry

thanks jerry.....
i just ordered the headlight switch and dimmer from LMC truck, and am looking for the relays...
im on my way to a correct wiring system for my headlights..

leonard

I bought a new universal switch for lights but with only three contacts, one for batt and do I double up on the other lights?
1942 chevy p/u