Headlight troubles.
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Headlight troubles.
Ok just so you know I'm 17 and don't a whole bunch about trucks yet. I've never really had anyone show me what to do. So, I might know exactly what you're talking about.
I bought new halogen headlights, because one of the old headlight was busted. When I first put them in they worked great. Now for the last 2 weeks I can't see more than 5 feet in front of the truck. I replaced the battery 2 days ago and it didn't help at all. Any suggestions?
I bought new halogen headlights, because one of the old headlight was busted. When I first put them in they worked great. Now for the last 2 weeks I can't see more than 5 feet in front of the truck. I replaced the battery 2 days ago and it didn't help at all. Any suggestions?
Laughing Gas
Joined: Sep 2012
Posts: 1,100
Likes: 6
From: Georgia
Assuming the headlights are aimed correctly (there are various instructions on the net on how to do it yourself and get it close) check the voltage at the headlights.
Make sure you're getting 14+ at the socket that plugs on to the bulb.
Start the car, turn on the lights and any other accessories, like heater blower.
Test between the pos and negative posts of the battery, to make sure your meter is working and the charging circuit is good. Should be 14+ volts
Test between the high beam connector and the ground connector. If it's 14+, you're good so repeat for the low beam.
If not 14+ test between the high beam connector and the battery.
If it's 14+, you have a ground issue between the socket and battery.
If still not 14+, test between the pos side of battery and ground connector on light socket.
If it's 14+ you have an issue in the positive circuit to the light.
If it's still not 14+ you have a problem in both pos and ground.
Repeat for low beam.
Repeat for other headlamp.
Make sure you're getting 14+ at the socket that plugs on to the bulb.
Start the car, turn on the lights and any other accessories, like heater blower.
Test between the pos and negative posts of the battery, to make sure your meter is working and the charging circuit is good. Should be 14+ volts
Test between the high beam connector and the ground connector. If it's 14+, you're good so repeat for the low beam.
If not 14+ test between the high beam connector and the battery.
If it's 14+, you have a ground issue between the socket and battery.
If still not 14+, test between the pos side of battery and ground connector on light socket.
If it's 14+ you have an issue in the positive circuit to the light.
If it's still not 14+ you have a problem in both pos and ground.
Repeat for low beam.
Repeat for other headlamp.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Tom's instructions are excellent. However, I fear you may have the dreaded "failing headlight wiring" problem and if you spend much time with the headlights on may melt many other wires as well. These trucks have a problem with small wiring in the headlight circuit as well as poor connectors. This frequently causes the wire (brown I think) going into the headlight switch to get so hot it melts the insulation, which can cause shorts into other circuits or even to ground.
So, before keeping the lights on for very long testing I would suggest you investigate the wires close to the headlight switch and the switch itself. Look for melted insulation. Turn the lights on and check for heat - but don't get burned. Once the problem starts it becomes a vicious circle, with poor connections giving more heat which causes even poorer connections.
So, before keeping the lights on for very long testing I would suggest you investigate the wires close to the headlight switch and the switch itself. Look for melted insulation. Turn the lights on and check for heat - but don't get burned. Once the problem starts it becomes a vicious circle, with poor connections giving more heat which causes even poorer connections.
Laughing Gas
Joined: Sep 2012
Posts: 1,100
Likes: 6
From: Georgia
Ideally, and it's on my to-do list, is install two relays, one for the high beams, one for the low beams, wire them to feed right from the hot side of the starter relay and trigger them with the stock headlight circuit which will then only have to supply a minimal amperage.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Ideally, and it's on my to-do list, is install two relays, one for the high beams, one for the low beams, wire them to feed right from the hot side of the starter relay and trigger them with the stock headlight circuit which will then only have to supply a minimal amperage.
Laughing Gas
Joined: Sep 2012
Posts: 1,100
Likes: 6
From: Georgia
True. If the wiring/connectors are deteriorated, fix them, then install relays.
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FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Unfortunately for Nick, replacing both headlights with new ones may have inadvertently triggered the melted-wire problem. Not only did he double the current by replacing one that didn't work with one that did, he replaced the tired one with a fresh one. Which is exactly what I would have done. But new bulbs pull slightly more current than old ones. So if the wiring was marginal....
However, all that is speculation and let's hope he just has a bad ground. Actually it would take two bad grounds, which is why I don't think that is the problem. Unless the radiator support's ground is bad, which is the common link.
However, all that is speculation and let's hope he just has a bad ground. Actually it would take two bad grounds, which is why I don't think that is the problem. Unless the radiator support's ground is bad, which is the common link.
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Senior User
Joined: Dec 2013
Posts: 143
Likes: 0
From: Lyman, SC
There are relay harnesses available for maybe $35 that are easy to connect and replace the factory wiring. Your old headlight plug goes into the harness and activates the included relays. You simply connect the ground and power to points of your choice. Here's an example of one for the old T3/H4 style plug:
http://www.summitracing.com/parts/UPD-34263/
Also, don't worry if you burn something up. You can still get replacement smoke to put back in it.
http://www.summitracing.com/parts/UPD-34263/
Also, don't worry if you burn something up. You can still get replacement smoke to put back in it.
Laughing Gas
Joined: Sep 2012
Posts: 1,100
Likes: 6
From: Georgia
There are relay harnesses available for maybe $35 that are easy to connect and replace the factory wiring. Your old headlight plug goes into the harness and activates the included relays. You simply connect the ground and power to points of your choice. Here's an example of one for the old T3/H4 style plug:
http://www.summitracing.com/parts/UPD-34263/
http://www.summitracing.com/parts/UPD-34263/
Senior User
Joined: Dec 2013
Posts: 143
Likes: 0
From: Lyman, SC
It's only $35 to find out ha ha.
I've got one at home I'll take a look at tonight. It's not the same brand but most likely the same otherwise. Seems it might've been 14AWG on the power and grounds. There's also some on ebay and Amazon with ceramic plugs. One of the big benefits is getting rid of a whole heap of the power transmission path that the headlights use.
I've got one at home I'll take a look at tonight. It's not the same brand but most likely the same otherwise. Seems it might've been 14AWG on the power and grounds. There's also some on ebay and Amazon with ceramic plugs. One of the big benefits is getting rid of a whole heap of the power transmission path that the headlights use.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Assuming 65 watt headlights, at 12v they would be pulling ~11 amps. The spec for three 14 gauge wires running in a cable is 20 amps, and that's for long runs and encased in a sheath. But the kits have short runs of wire and it isn't in a sheath like Romex is so #14 is fine for this application. In fact, the biggest potential problem is the connectors, which are frequently cheap 1/4" quick disconnects which sometimes don't make solid connections. So I would look for a kit that has good connectors.
Senior User
Joined: Dec 2013
Posts: 143
Likes: 0
From: Lyman, SC
The kit does at least have a separate power lead for each light, it's not a single lead wired across the bulbs in parallel. The bit about the connectors is right though.....I remember that the terminals were kinda like a packard style crimp. I popped the ones that connect to the headlights out and hit them with some solder.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Even soldering some of those connectors won't truly "fix" the potential problem. There are good quick disconnect connectors and there are cheap ones. The latter have very little material in them and little spring pressure so they don't make a good connection. A poor connection can create heat, which takes the spring out of the metal, which creates a poor connection, which creates heat, which......