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Additional lights and damage to Headlamp Switch


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Hi,

My owners manual states:

 

”Adding lights or electrical devices to the headlamp/park lamp circuit without a separate relay can damage the headlamp switch and wire harness.”

 

Further and more specific to my 3500, it states: “All Ram pickup models with cab clearance lights or any 3500 models must add a relay to the circuit before drawing any current from the headlamp switch.”

 

I am going to be hauling a Gooseneck and I’m wanting to know if anyone has a relay for the additional lighting on their trailer. 

 

 

Thanks Leaky

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  • Staff

I wonder why the owners manual says that when there's a trailer plug ready to go next to the receiver hitch. I have the camper package and even though it is a camper and not a trailer I still used the trailer plug for the slide in camper. Now.... my headlight switch was getting so hot when the camper was hooked up I thought it might melt the dash. Not knowing anything about using relays back then, I installed a heat sink for the switch using a long piece of copper tubing. So far 13 yrs its been okay and I do have the cab lights.

 

Now that you brought this up.....Honestly, I'm wondering if I'm causing a slow death to my headlight wire harness.

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  • Owner

Depends on how it's wired and what kind of lights you are using. Like my HID headlights are half of the power draw at a 35w now. Then the driving likes are a mere 18w now compared to the four 100w spotlights I was using. Then marker lights from the old 18w down to 3w in LEDs. 

 

Always best to use lighting with lower wattage requirements than going with more heavy light. I use to have problems with the four 100w spotlights blowing fuses, burning up relays, and just eating bulbs every 6 to 9 months. Now converted to HID and LED problems are gone. 

 

Using relays and separate fuses to power optional lights are the only way to go. Way less loading on the alternator and batteries. 

Edited by Mopar1973Man
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My citing from the manual really surprised me ESPECIALLY since Truck came with a TOW package, the 7way plug, etc.

 

But come to think of it, the  manufacturer also gave me the engine mounted Carter Lift Pump that was incapable of providing life support to the VP 44, a pump that was also not isolated with a relay to prevent high current draw on the ECM.  With that, I can only assume this was but a minor albeit very minor oversight in the design process.

 

JAG1’s experience serves to justify the expense of my onboard Fire Extinguisher for the imminent Class Charlie fire drill on the remaining “parts” of my Crater Dash.  A drill I think I will forego. 

 

So, like the Lift pump, I guess Ill error on side of caution and isolate Headlight switch too.

 

Appreciate the feedback and welcome work-arounds.

 

Thanks

Leaky

 

 

 

 

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You might want to look into a headlight relay harness that draws the headlight current from your battery’s and not the switch, although the trailer wiring has its own relay and fuses it should not effect your headlight switch at all the way I understand it.

 

I installed the dual sportheadlight relay harness when I upgraded headlights, not becomes I had issues with headlight switch getting hot but it was more to the fact I was doubling the draw on the factory headlight switch with the new dual headlights, in which probably would have caused the switch to overheat and melt.

 

another thing to consider if your switch is getting hot is to not use the dimmer as in the more it’s dimmed it creates more resistance thus creating the heat, also a dirty switch, oily gunk and whatever else is on it can lead to excessive heat.

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  • Owner

The headlights on our truck...

 

+12V -> Fuse -> Bulb <- Multifunction switch <- Headlight switch <- GROUND

 

Our headlight switch controls the ground. The dimmer switch toggles the ground to the lo or hi legs. 

 

Now if you just pony up and go to Morimoto HIDs then that whole problem goes away. Lightweight 35w HID bulbs, the power is drawn straight from the battery. Everything is controlled by a single relay.

 

I've done the Sport headlights. By the original design, you need 4 fuses and 4 relays. Then converting everything over to that system which still you end up with more electrical load on high beams you drawing 17 Amps total at 240 watts for four 60w high beam bulbs burning. 

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On 4/19/2019 at 3:45 PM, Mopar1973Man said:

The headlights on our truck...

 

+12V -> Fuse -> Bulb <- Multifunction switch <- Headlight switch <- GROUND

 

Our headlight switch controls the ground. The dimmer switch toggles the ground to the lo or hi legs. 

 

Now if you just pony up and go to Morimoto HIDs then that whole problem goes away. Lightweight 35w HID bulbs, the power is drawn straight from the battery. Everything is controlled by a single relay.

 

I've done the Sport headlights. By the original design, you need 4 fuses and 4 relays. Then converting everything over to that system which still you end up with more electrical load on high beams you drawing 17 Amps total at 240 watts for four 60w high beam bulbs burning. 

So where does one find these Morimoto HID’s and what can I expect to pay?

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On 4/19/2019 at 7:53 AM, Mopar1973Man said:

Depends on how it's wired and what kind of lights you are using. Like my HID headlights are half of the power draw at a 35w now. Then the driving likes are a mere 18w now compared to the four 100w spotlights I was using. Then marker lights from the old 18w down to 3w in LEDs. 

 

Always best to use lighting with lower wattage requirements than going with more heavy light. I use to have problems with the four 100w spotlights blowing fuses, burning up relays, and just eating bulbs every 6 to 9 months. Now converted to HID and LED problems are gone. 

 

Using relays and separate fuses to power optional lights are the only way to go. Way less loading on the alternator and batteries. 

Mike, with exception of HID are ALL of the other lights on your Truck LED and if so any issues...like with turn signals. Thanks Leaky

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Still pondering the HID and the DIY or Plug & Play option. My need to see how much Equity I have in my home to obtain a loan.

In interim , I’m sold on the LEDs and want to covert all possible incandescent to LED.

Sylvania ZEVO has 3157’s but they have caption “For off-road use only.”  They come in a Red White and Amber. They are alleged to be Super Bright.

Q1.  Has anyone used these ZEVO? If so, any issues with inspections, or late evening roadside chats with law enforcement?

Q2.  The clearance lights on side of my Dually Fenders are Clip-in Hella Brand, and bulb’s are not accessible. Is there an aftermarket LED replacement?

Thanks

 

 

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  • 1 month later...

Back in the late 90's I towed a 40' gooseneck all over the USA (a lot of lights on trailer that size) with a 1997 3500 Dodge, I melted a headlight switch when the truck was almost new, I put in a new switch, it melted in short order also.

 

Then I found out Dodge had a recall/update on the 3500's headlight switches, kit came with a pigtail, switch, and relay.  

 

I had a dealer do the recall. That switch lasted a month. Melted it also. Even with the relay it still melted the switch.

 

Went back to the dealer. They tried to blame the size of the trailer I was pulling, the lighting having too much draw on the switch. My trailer just had DOT required amount of lighting. It was not lit-up like a xmas tree like some trailers I saw.  

 

So I came up with a system to bypass the headlight switch, for my trailer lights. 

 

I put a toggle switch on the dash, ran a power wire to the switch from the battery (inline fuse in between) then from the switch out to the back of the truck, I removed the taillight wire in the trailer plug capped it off, and ran the wire from my toggle switch in it's place. 

 

I towed that 40' trailer, with that truck for almost 300,000 miles, never melted another head light switch. 

Edited by 24Vdodge
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  • Owner

Should have trailer relay in the PDC. Even my 1996 Dodge has a trailer relay.

 

But... If the trailer is not wired to that relay but the tail light wiring of the truck of course the headlight switch will get hot.

 

This problem came from the 1st gen truck that had no trailer relay at all. But was resolved in 1994. Biggest problem is did any one modify wiring on the truck?

 

exterior-2.jpg

Edited by Mopar1973Man
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5 hours ago, dripley said:

Sounds like the the relay was not i stalled right. The relay should have done the same thing your toggle switch and wire did, take the load off the switch.

 

Yeah that would not surprise me. Some dealers are not trustworthy. 

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