Problem with headlight relay?

blulightman · Post by **blulightman** » February 2, 2009, 9:13 pm

I was completing my headlight relay wiring and as I was attaching my ground plug I got a spark when it contacted my radiator support. I touched it again and my headlight came on! Backtracking to my starter relay my wiring is correct but on each relay the center #87 blade is hot. My switch leads aren't, the #30's are as they should be. When I checked my headlight plug, all three terminals are hot, but only on the pass side. Has anyone experienced this? I'll be starting my rewiring project soon(maybe sooner), but currently have PO integrations, one of which might be influencing this symptom. Can relays be my problem? I used Ford OEM's with the Bosch pattern. I'm puzzled.

ICEMAN6166 · Post by **ICEMAN6166** » February 2, 2009, 9:27 pm

i ued bosch relays and bosch pigtails with the correct plug end.

sounds like you have power going thru a ground wire as only the red or green wire on the headlight should be hot at any time, black is the ground wire.
(unless you did like me and added an extra switch so high and low can be lit at the same time, then both red and green would be hot if the switch was on)

blulightman · Post by **blulightman** » February 2, 2009, 9:37 pm

The ground wire was actually plugged into the headlight. Hopefully my plugs at the headlight are correct, I have high at center, low at inside and grounds at outside.

blulightman · Post by **blulightman** » February 2, 2009, 9:45 pm

I used the schematic and thread from this forum, cant understand why the #87 would be hot without the headlight switch firing it

blackagatha · Post by **blackagatha** » February 3, 2009, 2:03 am

try some new relays. Or just one new relay for starters, to see if that's the problem. They may have gotten overheated or arced out and the contacts stuck??

blulightman · Post by **blulightman** » February 3, 2009, 2:50 am

Blackagatha, you mentioned in your other response that #87a had a lesser gauge wire? That is possibly the key. the thread I used for my guide didnt mention a difference with the two. I would assume that the heavier gauge would power the hi beam and 87a powers the low. not knowing, I might need to switch those, no pun. thanks again

Bills 66 · Post by **Bills 66** » February 3, 2009, 5:16 am

go to the bottom of page and see the different relays

http://fordfuelinjection.com/?p=42

blulightman · Post by **blulightman** » February 14, 2009, 6:30 pm

In your response to my question, you attached the relay schematic and I I noticed there wasnt a contact labeled as 87a. Are you using a 4pin relay? I have checked nine different 5 pin relays that I have and all have continuity between the 30 and 87a pins with no current applied. When current is applied, both 87a's are hot as a result. Could I possibly have nine damaged relays? For night driving, I've been stuck having to pull and replace the 20A fuses or my lights will stay on, because my 87a's are hot. any wisdom, anyone?
thanks, Leonard

jwh f-100 · Post by **jwh f-100** » February 14, 2009, 6:51 pm

Leonard,

On your truck you should not be using the 87a terminal...

You have two relays, one is for high beam and one for low. On each relay should be two wires on the #87 terminal. One wire form each #87 terminal needs to go to each light.

The only reason I can see to use 87a is if you wanted DRL, but that would require a third relay...

blulightman · Post by **blulightman** » February 14, 2009, 7:01 pm

thanks Jason. I guess I wont print any more hint threads that have beers on the parts list. I have 4pin relays to swap. Luck!

jwh f-100 · Post by **jwh f-100** » February 14, 2009, 7:06 pm

You can use the five pin relays just leave 87a empty.

blackagatha · Post by **blackagatha** » February 15, 2009, 4:26 am

blulightman wrote:Blackagatha, you mentioned in your other response that #87a had a lesser gauge wire? That is possibly the key. the thread I used for my guide didnt mention a difference with the two. I would assume that the heavier gauge would power the hi beam and 87a powers the low. not knowing, I might need to switch those, no pun. thanks again

gotta have 2 relays. like they said, 87A is extra

it just struck me though, If we were to hook the 87A wire from the Hibeam relay into the trigger lead for the low beams, that would be the simplest way to have both beams on simultaneously when the his click on- as it is, the lows turn off when the highs come on.

ERR, SCHIT, I'm thinking wrong. It would make feedback thru the wire and turn on the highs, dimly when the switch says low beams. You would need a DIODE on the wire (electrical check valve) to make the electricity only go one way.

ICEMAN6166 · Post by **ICEMAN6166** » February 15, 2009, 12:11 pm

i have a little chrome pull switch that keeps the low beams on when you press the dimmer switch to turn the high beams on. i never turn that switch off so high is always both beams.

blulightman · Post by **blulightman** » February 15, 2009, 1:54 pm

Thanks for the input gentlemen, what an awesome difference!

blackagatha · Post by **blackagatha** » February 16, 2009, 1:10 am

ICEMAN6166 wrote:i have a little chrome pull switch that keeps the low beams on when you press the dimmer switch to turn the high beams on. i never turn that switch off so high is always both beams.

yeah, I dont see much reason to turn them off either. I need to find a diode and wire it in... sans switch.

Problem with headlight relay?

Problem with headlight relay?

Hey Iceman166