P500 Headlight question

[Bastardchild]

Anybody know why my headlights dont work even though I have 13 volts to the plugs in each headlight housing? The bulbs wont light up when plugged in, but I can run a couple jumper wires off of one of my Milwaukee batteries and they light up just fine. Also, the plugs have voltage at them even if the switch is off. However, if I ohm the switch out on the 'tone' setting with the switch off it doesnt give me tone, but when I turn the switch on it does give me tone, which is correct. I did have a critter chew on my MAP sensor wires and Hondasxs is gonna make me a new pigtail for me to splice onto my wire harness and plug into my MAP sensor to get my check engine light to clear on my dash. Do you think the headlight problem could be caused by this? On the other hand, now that I think of it, the check engine light has been flashing for months because of the MAP wires, but Im pretty sure Ive used the headlights while the check engine light has been blinking. Anyway, Im not very good at the wiring on vehicles. I know just enough to be dangerous. Any ideas?

 

[Admin]

 

[Neohio]

are those LED?
They might be polarity specific.
might have to pop the pins out of the headlight plug and swap em side to side.

 

[Bastardchild]

are those LED?
They might be polarity specific.
might have to pop the pins out of the headlight plug and swap em side to side.

No, not L.E.D.s They are the factory 2016 bulbs. Ive never changed them that I can remember. I just popped one out again and it lit up either way from my Milwaukee battery, just to check on your theory. Still stumped lol

 

[Neohio]

put the ground from the meter on the battery or chassis ground.
Does the 500 use a switched negative for headlights?

 

[Bastardchild]

put the ground from the meter on the battery or chassis ground.
Does the 500 use a switched negative for headlights?

I put it to one of the frame bolts under the fenderwell earlier and it still gave me 13 volts on the hot wire at the plug.

 

[Neohio]

Wiring diagram shows power coming from brown wire from lighting relay.
green is ground.
you might have a faulty/bad lighting relay? or bad wiring, something somewhere telling the relay to energize.

 

[Bastardchild]

I also cleaned the ground junction back by the battery where all the green wires bolt to the frame along with the negative battery wires. Cleaned it and all the connections there and put dialectric grease. It also has a brand new battery I just put in Friday, and I cleaned those connections Friday when I put the battery in.

 

[Neohio]

check resistance from light plug to ground. also 12v side to battery.
you might have a weak wire that fails with a load applied.

 

[Bastardchild]

Wiring diagram shows power coming from brown wire from lighting relay.
green is ground.
you might have a faulty/bad lighting relay? or bad wiring, something somewhere telling the relay to energize.

Let me check the relay. I would think though with voltage at the plug the bulbs would light up. Im not good with this wiring stuff. Thanks for your help btw

 

[Neohio]

Let me check the relay. I would think though with voltage at the plug the bulbs would light up. Im not good with this wiring stuff. Thanks for your help btw

I had a chev truck once that would light a test light bulb up, but wouldn't light the actual bulb. we found some weak wiring, repaired it and everything was good.

 

[Bastardchild]

I had a chev truck once that would light a test light bulb up, but wouldn't light the actual bulb. we found some weak wiring, repaired it and everything was good.

Gotcha. Too thin/weak for the amperage draw I guess?

 

[Neohio]

Gotcha. Too thin/weak for the amperage draw I guess?

yep,
still doesn't explain the power at plug with key off though.

 

[Bastardchild]

Heres another thing I just noticed. I can get 13 volts to either side as long as both bulbs are out of the plugs. If I put a bulb in one side, the other side will have no voltage at all. I repeated this process for both sides and it was the same. I ran another ground wire from the negative terminal of the battery up to the fenderwell and used it as the ground and ran a hot jumper wire out of the bulb plug socket to light up the bulb and it didnt work. However, I ran a long hot wire from the positive post of the battery and ran a small jumper out of the negative side of the bulb plug and hooked the long positive jumper and short negative jumper to the bulb and it lit up. So its a hot wire issue and not a ground wire issue Im guessing.

 

[Bastardchild]

Well looky here. A relay with the side busted out of it...Id bet my paycheck thats the lighting relay. Gonna order one and when it comes in cross my fingers and hope the lights work. If it dont, then back to square one. Thank you for your help @Neohio

 

[Neohio]

easy solution is remove relay, use jumper and see if lights light.

 

[Bastardchild]

easy solution is remove relay, use jumper and see if lights light.

Good news and bad news. I took one of the other relays out that had the same serial # on it and put it in the lighting relay spot. The lights fired up and turned on and off like theyre supposed to. Then I decided to pull all 4 relays and clean and dialectric grease everything. Well, now I have to order 3 relays instead of 1. Me wiggling them out broke a leg off of 2 of them and the male leg is still down inside the block in 2 of the relay locations. Lol oh well. Im putting this damn thing up and unhooking the battery so the damn thing dont burn to the ground while Im asleep tonight lol. I will order the 3 relays when I get a chance. Thanks again for all your help!

 

[Neohio]

Always around to help! At least you save the shipping on buying 3 different times.

 

[Bastardchild]

Always around to help! At least you save the shipping on buying 3 different times.

Thats a good way to look at it lol

 

[BBB]

Are they available at your local auto parts store?

 

[Bastardchild]

Are they available at your local auto parts store?

Thats a good question. When I go back to work tomorrow I will stop into an auto parts store between jobs and see.