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Old 02-18-2018, 06:54 AM   #1
Dwyert4
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Lost dash, some, brake and side marker lights

(Title should say dome not some)So last night I lost all lights but my headlights and blinkers. I'm not great with electrical, so i have no idea where to start. I have led side markers and brake lights. It's a 70 long bed. What would cause all of this to happen and the headlights and blinkers still work?
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Old 02-18-2018, 09:09 AM   #2
Barnfind46
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Re: Lost dash, some, brake and side marker lights

Check your fuses.Then start checking your connections.I would start with the plug on the headlight switch.Check all the grounds and make sure the plug on the dimmer switch is clean.If those all check out then start checking the harness for bare wiring from previous owners that might short out when the truck is moving. Is this the first time you have had problems? Wiring is not too difficult but many people get frustrated.Take your time and be patient.
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Old 02-18-2018, 09:17 AM   #3
Dwyert4
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Re: Lost dash, some, brake and side marker lights

I'm getting ready to start with the fuses now. That's within my ability. 😀. It's the first time this has happened. Now that you say it , I did from time to time have to mess with the switch. But it only affected the side markers. I do know harnesses are in the near future because the PO did a number on them. Thank you for some direction cause this is all kinda new to me. I'll keep you updated.
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Old 02-18-2018, 10:28 AM   #4
Dwyert4
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Re: Lost dash, some, brake and side marker lights

Ok,so the 20amp til stop/park dome fuse was blown. Changed it and it fried the second I turned the lights on. So bad switch? Do you have to pull the dash to change it? Just bear with me cause like I said this new to me. And thanks ahead of time.
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Old 02-18-2018, 11:15 AM   #5
dmjlambert
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Re: Lost dash, some, brake and side marker lights

To change the switch you don't need to remove anything else. You just reach up behind the dash to the switch and find a little button on top of it. That button lets you release the knob. Push the button gently and pull the knob and it should come off with a metal stick attached. You may need to wiggle the knob around and play with the button to get it done. It helps if you stick your tongue out, furrow your eyebrows, and mutter a few words of encouragement to yourself under your breath. After the knob is off you can take off the bolt that holds it from the front and unplug it.

It's possible that would be blowing a fuse, but it is also possible some wiring is shorted.

Check your wiring where it goes through the driver side fender to the headlight area, and where it branches off to go to the various lights, including over the top of the radiator to the passenger side. Mine had damage and I repaired it. Also there is a 4 conductor wire that comes out of the middle of the firewall behind the engine and goes under the truck to the rear lights. Check that wire for condition, mine had damage. The rear light wiring where it branches off and goes to the various lights I think is often damaged because people added trailer wiring. Check to see if all that looks OK.

If your fuse continues to blow after you install a new switch, you'll have to get more involved with tracking down the short.
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Old 02-18-2018, 11:40 AM   #6
Dwyert4
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Re: Lost dash, some, brake and side marker lights

How did you know I stick my tongue out when I work?... Thanks for the advice. I'm going to get a switch now. I did change the fuse again and brake lights, dome and cargo worked. So I'm thinking switch for sure. Thanks I appreciate the help.
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Old 02-18-2018, 02:38 PM   #7
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Re: Lost dash, some, brake and side marker lights

Quote:
Originally Posted by Dwyert4 View Post
Ok,so the 20amp til stop/park dome fuse was blown. Changed it and it fried the second I turned the lights on. So bad switch? Do you have to pull the dash to change it? Just bear with me cause like I said this new to me. And thanks ahead of time.
What you are most likely to find is that you have a short to ground in one of the marker lights or the parking lights. Since the turn signals are working it tends to rule out the parking/turn lights,which leaves the marker lights or the wiring that goes to them. This includes the wiring that goes to the parking lights both front and rear.

Here is how the circuit is powered.
The fuse panel is powered by a hot red wire that is fused by the parking
lights, dome light, and stop light. On the other side of the fuse is an orange wire which carries power to the stop light switch, the dome light, and the headlight switch.

It appears that you are not blowing this fuse until you turn on the headlight switch. When you do that you send power from the orange wire to the brown wire on the switch that carries power to all of the tail, parking and marker lights.

Here is a picture of the fuse panel and in the lower right is the fuse panel with the red wire powering the fuse for the stop/tail lights and the orange wire from the other side of the fuse that goes to the dome light fuse, and the stop light switch, and the headlight switch.

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This is a picture of the headlight switch and the wires that go to it and what they power. You can see that the orange wire powers the brown wire that feeds the parking lights and markers.



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This one shows the orange wire going to the headlight switch in the lower right.

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The wires below it are the tail light and stop light wires going to the back of the truck.

You may have a wire shorted in that harness, or one of the lights powered by the brown wire, which will go to the tail lights, or the license plate light, or the rear markers if the 70 has those. The license plate light is a common place for a short to ground.

You can isolate the front lights from the rear lights by disconnection the harness on the engine side firewall just above and to the left of the distributor. This is the rear light harness and if you disconnect it and then turn on the headlight switch and don't blow a fuse, then the problem is in the rear of the truck or in the harness that runs along the frame.

If you still blow a fuse when you turn on the headlight switch then the short is in the cab or in the front of the truck. the wires that feed the front parking lights are purple and the markers are brown.
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Old 02-23-2018, 08:18 PM   #8
Dwyert4
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Re: Lost dash, some, brake and side marker lights

So changed switch. Still a problem. Then I started the wire chase. Somebody liked cutting and using butt connectors. Looks like a harness is in the very near future. Fun fun.
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Old 02-23-2018, 09:37 PM   #9
dmjlambert
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Re: Lost dash, some, brake and side marker lights

I was hoping it was going to be your switch, because that is easier. There is really not all that much wire in the truck, so if you want to track down the problem and at least temporarily fix it, you may find that it is not too hard. I had about a dozen wires that were eaten by rats. I cut out the bad part and soldered a length of good wire in the gap, and used heat shrink tubing over the solder connections, and non-adhesive vinyl tape to bundle the wires again like factory. The rest of my harness was in surprisingly good shape. But almost every switch in the truck was bad, including headlight switch, dimmer, turn signal, heater.
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Old 02-24-2018, 06:05 PM   #10
Dwyert4
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Re: Lost dash, some, brake and side marker lights

So, now I'm starting with tearing out old stereo system. Im finding most of the hodge pode wiring involves the audio and alarm. Im yanking it and going from there. Its old 90's stuff anyway. Also it allows me to check out the backs of the cab. Ill update with progress. Im also running through al the grounds and making sure im good there. I love this site! You guys are the best.
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