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Discussion Starter #1
So my 1978 K30 started having break light issues after not driving the truck for a while. I had no break lights although my break light switch had power. I checked my grounds and found a few bad ones but still didn’t fix the problem. So as I didn’t really have time for pulling her apart I ran a jumper off the switch and tried to just bypass the problem. But when I looked at my wiring to the rear of the truck I discovered that chevys seem to combine the left and right turn signal wires to get a break light. So I made a splice to them and got break lights, but now I had no turn signals, so I installed sum inline diodes which gave me my turn signals back and brake lights but they will not work together. So now basically I hit my breaks and the turn signal does not work on the rear, the relay clicks but no signal. So now I’m stumped, any advice?

Mike
 

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I would suggest you stop breaking lights, especially the one in your melon

 

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Argh... speaking of being charitable...
Two things you need to check after you remove the butchering job.
1. The rear harness connector at the back of the truck.
2. The tail light ground behind the drivers side tail light housing.

Alex.
 

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So my 1978 K30 started having break light issues after not driving the truck for a while. I had no break lights although my break light switch had power. I checked my grounds and found a few bad ones but still didn’t fix the problem. So as I didn’t really have time for pulling her apart I ran a jumper off the switch and tried to just bypass the problem. But when I looked at my wiring to the rear of the truck I discovered that chevys seem to combine the left and right turn signal wires to get a break light. So I made a splice to them and got break lights, but now I had no turn signals, so I installed sum inline diodes which gave me my turn signals back and brake lights but they will not work together. So now basically I hit my breaks and the turn signal does not work on the rear, the relay clicks but no signal. So now I’m stumped, any advice?

Mike
Here is your problem. You were in a hurry and screwed it all up when doing it right would have taken less time. You installed diodes to get turn signals!!! How is this approach quicker or easier????

 

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Why do people create more work and problems by rigging something rather than fixing it correctly.

Learn how to use a meter and read a wiring schematic, it's real easy with the internet now.

BRAKE ISSUE
 

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Why do people create more work and problems by rigging something rather than fixing it correctly. [/QOUTE]

Sounds like the Company i work for......They will spend twice as much money and take twice as long just to fawk it up worse.
 

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I like the guys that butcher the column because they need to replace an ignition switch
 

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Discussion Starter #13
The solution to the problem is somewhere in where my truck adds the signal to the break to the left and right turn signal ports, which I think may be in the junction box that comes out of my dash. My rear wiring is fine I have checked it. On our trucks what stops the signal from traveling from your left to right signal wire when combined to the break signal wire, power flows both ways, somewhere in my dash there must be sum soft of factory diode that isn’t work. How are the factory signals combined, I have power at my switch but between where that signal goes after the signal leaves the switch and were it combines with the L and R signal wire that comes off the power block in the engine compartment there’s a problem.

I agree jerry rigging seldom fixes anything and the whole truck could use a new harness but the 5 minutes I took to have signals instead of getting a VI was necessary. When I say I have no time I mean it work 18 hour days you have little time to eat and sleep never mind pulling out dashes to trance down wiring nightmares. And yes I am dyslexic and don’t spell very well, I’m not in this form for grammatical advice so if you’re not here to shed insight on wiring I’m not interested in hearing from you:flipoff2:
 

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The turn signal overrides the BRAKE (not break) light once the signal is turned on.

You need to unfuck the diode mess you made and return to the factory setup. Check and replace any faulty grounds and wires. And in a truck that old, there are probably a few.

The lamp socket could be worn out as well, and not providing a solid connection.
 

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. My rear wiring is fine I have checked it.
But did you pull apart the rear tail light harness connector under the back end of the truck and check for correct voltages when you are trying the various functions? Hint: this connector often gets corroded. In really bad cases the wires get corroded IN the harness extending from this connector. If thats the case, you need to correct this first.

Did your remove the drivers side tail light housing (not just the lens) and look at and give a bit of a tug on the ground wire screwed to the inner body? If this wire is corroded or broken guess what, no rear lighting. Bet you will find this wire is rock hard and the moment you touch it it will break off. Back track this wire until you find a good spot, and splice on a new section of wire. Solder it, and use some sort of sealing connector or adhesive lined (correctly sized) heat shrink to protect it. Then ty-wrap it to keep vibrations from shaking it to pieces.

And after you have checked all your sockets and lamps, report back.

Alex.
 

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60-87 chevys that i have seen (even those with little rust), have always had ground problems in the rear of the truck with the lights. grounding it to the bed isnt always gonna work, especially if you have a body lift...

you need to check all of your wires, like was stated above, and the connections to the back of the bulb cans in each light housing.

and like was stated, get rid of the fucking diodes.
 

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I am in the process of swapping columns in my junk. In my research I have found that the brake light power flows through the hazard and turn signal switches then to the proper lights. Could this be the same with your truck? Do you have a bad switch?
 
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