Headlights

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Boltrunner

Full Access Member
Joined
Jul 25, 2016
Posts
365
Reaction score
181
Location
Odin mn
First Name
Shane
Truck Year
1987
Truck Model
V20
Engine Size
5.7
So my wonderful blue bomb has another issue that i need to address. I need a new headlight switch. I know that because i need to wiggle and turn it like im turning on a woman lol. But aside from that my headlights only work when i turn on my beams. Other than that i turn on my lights make sure my dash lights are on then fight the high beams to stay on so i have 3 headlights instead of 2 or 4 lol. I know some switches need replaced but what would be the reason the headlights only turn on with the high beam switch
 

chengny

Full Access Member
Joined
Feb 22, 2012
Posts
4,086
Reaction score
1,008
Location
NH
First Name
Jerry
Truck Year
1986
Truck Model
K3500
Engine Size
350/5.7
So my wonderful blue bomb has another issue that i need to address. I need a new headlight switch. I know that because i need to wiggle and turn it like im turning on a woman lol. But aside from that my headlights only work when i turn on my beams. Other than that i turn on my lights make sure my dash lights are on then fight the high beams to stay on so i have 3 headlights instead of 2 or 4 lol. I know some switches need replaced but what would be the reason the headlights only turn on with the high beam switch

If you have quads, you might want to read these threads and confirm that the correct lamps are installed and properly wired:

http://www.gmsquarebody.com/threads/no-headlights.16578/#post-319205

http://www.gmsquarebody.com/threads/new-headlight-harness-update-help.16224/
 
Last edited:

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
29,082
Reaction score
23,863
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
The most likely cause would be the headlight dimmer switch, or just simply some burned out headlights.

But there could be many other reasons for the problems too. But I would start by testing the headlights first.
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,449
Reaction score
4,552
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,70,48
Truck Model
Suburban k10, bonanza k10, c30 C&C, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350
Heavy duty headlight harness will keep that switch from melting! It doesn’t get hot to the touch after being on for a minute like the factory way does.

Also had a noticeable light output increase.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
29,082
Reaction score
23,863
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Heavy duty headlight harness will keep that switch from melting! It doesn’t get hot to the touch after being on for a minute like the factory way does.

Also had a noticeable light output increase.

From a reliability standpoint, the aftermarket heavy duty harnesses are overrated. I've owned way more than my share of GM cars and trucks and I have yet to replace a single headlight switch. There's been dimmer switch failure and a couple headlight connectors that needed the contacts cleaned. That's it. Not a single cooked part.
 

Boltrunner

Full Access Member
Joined
Jul 25, 2016
Posts
365
Reaction score
181
Location
Odin mn
First Name
Shane
Truck Year
1987
Truck Model
V20
Engine Size
5.7
Which are high and which ones are low beams?
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,449
Reaction score
4,552
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,70,48
Truck Model
Suburban k10, bonanza k10, c30 C&C, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350
From a reliability standpoint, the aftermarket heavy duty harnesses are overrated. I've owned way more than my share of GM cars and trucks and I have yet to replace a single headlight switch. There's been dimmer switch failure and a couple headlight connectors that needed the contacts cleaned. That's it. Not a single cooked part.

The one on my suburban fried the connector and the switch, I also have a 70 c10 that did the exact same thing. I also did a before and after and with the factory setup the switch gets seriously hot after barely a minute, after I did the harness the switch it honestly didn't get hot really at all after ten minutes, that being said I haven't driven it yet so that's not saying much but I think with that result right off the bat, that makes me feel a lot more comfortable that I wont possibly lose all my lights or something at some point.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
29,082
Reaction score
23,863
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
The one on my suburban fried the connector and the switch, I also have a 70 c10 that did the exact same thing. I also did a before and after and with the factory setup the switch gets seriously hot after barely a minute, after I did the harness the switch it honestly didn't get hot really at all after ten minutes, that being said I haven't driven it yet so that's not saying much but I think with that result right off the bat, that makes me feel a lot more comfortable that I wont possibly lose all my lights or something at some point.

I did a count because I got curious. Unless I'm forgetting one or two, I've had 44 GM cars and trucks with the newest being an '00. Not a single one with a melted headlight switch or harness. I don't recall ever putting one in a customer's vehicle either.

That's not to say it doesn't happen. It's just not common at all in my experience.

Tops are low and bottoms are high.

To expand, the tops have a low and a high element. The bottoms are just a high element.
 

Dougnsalem

Full Access Member
Joined
Jan 13, 2018
Posts
1,143
Reaction score
1,312
Location
.
First Name
.
Truck Year
.
Truck Model
.
Engine Size
.
I did a count because I got curious. Unless I'm forgetting one or two, I've had 44 GM cars and trucks with the newest being an '00. Not a single one with a melted headlight switch or harness. I don't recall ever putting one in a customer's vehicle either.

That's not to say it doesn't happen. It's just not common at all in my experience
Mine melted. I had to do a quick (and nasty looking) solder job, just so I wouldn't have to worry about it.
You must be registered for see images attach


It's a year later, and I'm fixing it right. Putting this stuff in right now.....
You must be registered for see images attach


And yeah, normally I stick with real Bosch relays. I just had to try these. 60 ampers for like 15 bucks, for all of them. They even have a LED thingy to tell when the circuit is energized. We'll see how they work....
 

Camar068

Supporting Member
Supporting Member
Joined
Feb 5, 2014
Posts
4,152
Reaction score
3,006
Location
Kentucky
First Name
David
Truck Year
1986
Truck Model
K10/LM7 5.3/4L60e/np208/3.73/32"
Engine Size
10 yrs Air Force
might want to put a bead of silicon around the clear cap where it meets the base of the solenoid. Moisture may have an affect on them. The good thing about those is you can pop the cap off and clean the contacts. If it's a perfectly sealed box you should be alright.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
29,082
Reaction score
23,863
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Mine melted. I had to do a quick (and nasty looking) solder job, just so I wouldn't have to worry about it.
You must be registered for see images attach


It's a year later, and I'm fixing it right. Putting this stuff in right now.....
You must be registered for see images attach


And yeah, normally I stick with real Bosch relays. I just had to try these. 60 ampers for like 15 bucks, for all of them. They even have a LED thingy to tell when the circuit is energized. We'll see how they work....

Where did you buy that nifty setup?
 

Dougnsalem

Full Access Member
Joined
Jan 13, 2018
Posts
1,143
Reaction score
1,312
Location
.
First Name
.
Truck Year
.
Truck Model
.
Engine Size
.
Where did you buy that nifty setup?
eButt. The box and terminals were like 14 bucks. It's going in by my left headlight. Two relays for the lights, and two for the electric fans, I have yet to get. Leaves 2 free relays, and has it has fuses for all of them. Cheap China stuff, so we'll see how it works....
 

Dougnsalem

Full Access Member
Joined
Jan 13, 2018
Posts
1,143
Reaction score
1,312
Location
.
First Name
.
Truck Year
.
Truck Model
.
Engine Size
.
might want to put a bead of silicon around the clear cap where it meets the base of the solenoid. Moisture may have an affect on them. The good thing about those is you can pop the cap off and clean the contacts. If it's a perfectly sealed box you should be alright.
Yeah, the relays are "sealed". Not so good though. Lol. Inexpensive would be an understatement. The box comes with a cheap lid too.

You must be registered for see images attach
 

chengny

Full Access Member
Joined
Feb 22, 2012
Posts
4,086
Reaction score
1,008
Location
NH
First Name
Jerry
Truck Year
1986
Truck Model
K3500
Engine Size
350/5.7
Which are high and which ones are low beams?

This is how they are designed to operate:

You must be registered for see images attach


You must be registered for see images attach



Did you get a chance to look at those links above?

Make sure your lamps are A1's and they are wired right:

You must be registered for see images attach




You must be registered for see images attach
 
Last edited:

Latest posts

Forum statistics

Threads
42,056
Posts
908,167
Members
33,538
Latest member
Chuchito
Top