85' 720 - Nothing but Headlights

[mmitchell57]

This weekend I decided to attack the issue of the heater core not being used.  Previously the coolant lines were routed to by pass the heater. I figured i'd hook em up to see what would happen. Come to find out, niagra falls was in my cabin, but it was green. So, new plan, new heater core.  I put it off since it was about to be summer then the rain started. It's been raining for almost 3 weeks straight here. Finally, decided I need defrost. Well, went through the gambit of things this Saturday. Pulled the dash, fan, ac box, and heater core box. replaced it all. put it all back together. Nothing huge to note, but it was an all day experience. I re-applied weather stripping to all the boxes to insure I had a good seal. All back together and fire up the truck. I have great heat  now, almost too damn hot.  LIghts cut on all the way around. I cut off the truck to make sure I have enough coolant. Top it off, hop back in and fire it up. Bam, no dash lights, dome light, turn signals, brake lights, or taillights. It was about 9pm by the time I got there yesterday, so I left it for today.

 

I checked fuses, replace 2 15amp fuses I though were relative and no love. I got the dinging noise back for leaving my key in the ignition. One thing I remember this morning, I re-wired up the cig lighter and had left the light pushed in. I'm worried I fried something. I need some help figuring out what's going on here so I can drive it to work tomorrow. Let me now your thoughts.

[wayno]

4 posts in almost 5 years, your a talkative one, aren't you.  :lol:

Replace all the fuses, even if they look good.

[Charlie69]

When you pulled the heater and related parts out did you disconnect any black wires thar made contact to the firewall?  These are you main ground wires.  If you left it off this could cause your problem.

[mmitchell57]

lol, yes, I don't say much. I stay pretty busy with a full house.

 

Ok, i'll check all fuses and look for any loose grounds. Thank you.

[mmitchell57]

Ok, found a bad fuse that looked like it was good. That fixed the running, dome, and dash lights. I still don't have turn signals and brake lights. I found the stop lights fused and replaced it, no love. I'm convinced if it was a ground i'd have more issues. Let me know your thoughts.

 

in the center of the dash I have a red, pink, and black wire free. I'm assuming they were for the radio that doesn't exist any longer.  Under the left hand side of the dash I have a plug w/ about 8 connectors that doesn't match up to anything in the truck.

[mmitchell57]

Looks like the haynes manual and I are going to spend some time together tonight to figure out what's up. I'll look for black wires that are not grounded and see if I can find one I missed.

[Tinman]

On your turn signals, wiggle the hazard switch back and forth and see if they come back on.  The hazard switch is pretty common to cause problems.  Usually it's dirty, or you need to move it just a little bit to the on position to make contact for the signals.  Check the connectors under the bed for the lights.

[mmitchell57]

Will do. I've been out there digging around trying to find the culprit and just got back to the desk. I did find wiring diagrams on autozone for my year truck.

 

Below is a picture of the area around the battery. Directly to the right and top of the battery are a ton of connectors. Some of them are hooked up, some are not. I figure it's due to certain things in the engine bay not being there and the AC not being completely wired up.

 

 

The next pic is some cables I found under the dash that I didn't know what to do with. The only one I can't remember off the top is the black one w/ a white connector. The black/red and orange/blue is what I had hooked up to the cig lighter. No joy. It blew the fuse.

[mmitchell57]

On another note, here are some pictures of the dash being pulled and the venting system being redone.

 

This is most of it taken out w/ exception of the AC box. I had that out shortly there after. The fuzzy dice were a present from the kiddo when I had a 62 ford fairlane. I kept em.

 

Here a picture of all the cables I had floating around once I got all the venting back in. In basics, I went through and cleaned all the weather stripping and replaced it the best I could w/o getting to crazy. Spent about 15 bucks. I also clean and repaired the vent system control levers and the cluster of hell to the right that controls all the flaps. It was a nightmare getting all the flaps adjusted properly. The only ground cable in this whole setup that was on the frame was on the top most bolt of the AC box.

 

another shot for the hell of it.

[datzenmike]

The stop lamp fuse is the forth one to the left from the far right side of the fuse box. Need to know... does it blow as soon as you plug it in or only after hitting the brake pedal.

[wayno]

As Tinman said, cycle the 4 way switch several times, the brake/turn signals go threw that switch, make sure the 4 way switch is plugged in good also, as you may have unplugged it when you took the dash out, that depends on if you took the column cover off.

Do the 4 ways work?

[datzenmike]

The brake lights and the 4 way flasher run off the same fuse.

[mmitchell57]

The fuse in that spot is good now. I haven't had it fry since I replaced it originally. 

 

The is the 4 way switch the hazards?  I'll check that out. I'm on the verge of getting new flasher modules, but I don't wanna throw money at it when it's something simple.

[wayno]

4 ways=hazzards

[datzenmike]

Don't replace the module unless bad.

 

I found out years ago on a friend's 720 that the turn signals are disconnected when the 4 way switch in placed in the ON position. When turning the 4 ways OFF the switch travels too far and goes right past the connections that connect the turn signals back up. Moving the 4 way switch slightly towards the ON position connects them.

 

Now brake light... 

The fuse is now good so look at the switch on the brake pedal. Use a short length ow wire to connect those two wires on the switch. If the brakes now light up then the switch isn't working.

 

If brake lights are still not working see if the bulbs are burnt out.

 

If bulbs are good use a test light and see if there is 12 volts on the Yellow/Blue wire on the round connector that supplies the rear tail light harness. Maybe bad connection The plug should be near thee right rear tail light and frame rail. Strangely it connects to a Yellow /Red wire on the rear harness. You should have 12 volts with the brake ON.

 

If still no power look under the passenger seat for a 10 pin connector that joins the cab harness to the under body harness. Again it's the Yellow/Blue wire that should have 12 volts with the brake on. Maybe bad connection

[mmitchell57]

Don't replace the module unless bad.

 

I found out years ago on a friend's 720 that the turn signals are disconnected when the 4 way switch in placed in the ON position. When turning the 4 ways OFF the switch travels too far and goes right past the connections that connect the turn signals back up. Moving the 4 way switch slightly towards the ON position connects them.

I'll give that a run. I remembered I had a circuit tester / multi-meter so I whipped that out. Did a quick battery check to make sure it was reading good and it scored an A. So I tested the flasher circuit and the turn signal circuit and nothing. Not sure of the order to try the connections in. However, when the hazard switch is all the way back, I can a closed loop at 13.5 v on 4 of the terminals where in the closest to the driver I only get one set of terminals that register. Odd... I'll try the wiggle thingy. If that doen't do it I'll head up to auto zone and grab the flasher and hazard modules.

[datzenmike]

Hazard switch....

 

In the OFF position the Green and the Green/White wires should be connected. This will connect the turn signal flasher to which ever side the turn signal arm is turned to.

 

In the ON position the Green and the Green/Whiter wires are disconnected.

 

 

 

 

First do the 4 way flashers work????

 

If they do to quickly check the flasher unit for the turn signals swap the two flasher  units. If the 4 way stops working and the turns start working then the flasher was the problem.

[mmitchell57]

 

The big one is the hazard relay, the small is for the turn signals. Both the hazards and turns signals don't work. I flipped them and no love. I tried to see if I was getting juice at the fuse block but I got nothing. Not sure if that's something I'm doing or if it's supposed to be like that. Also did the wiggle the switch thing with no joy. I really don't want to have to pull the dash, but you do what you have to do.

 

Also, on the hazard switch, the green and green/white didn't work in either position. On wire I got action from was the red wire connecting to the green/white which was soldered in w/ the ground. I'm lost at this point.

[nerdistmonk]

The trick to the hazard switch weirdness is WD40, my turn signals went dead, had a funky switch, i stuck the straw nozzle of wd40 into the switch, pulled the trigger and didnt stop till there was foam coming out of the hole...problem solved, 2 months later still good. Make sure to work the switch back/forth while doing that.

[mmitchell57]

The trick to the hazard switch weirdness is WD40, my turn signals went dead, had a funky switch, i stuck the straw nozzle of wd40 into the switch, pulled the trigger and didnt stop till there was foam coming out of the hole...problem solved, 2 months later still good. Make sure to work the switch back/forth while doing that.

I'll give it a run tomorrow after work and let you know.

[mmitchell57]

Tried the wd-40 thing. I had liquid wrench. The switch sounds a bunch better when flipping it back and forth, however it didn't resolve the issue.  Is there any way to isolate the turn signal level from the picture to see if everything else works?  Another problem I noticed was the the brights will cut on if they are off and I hit the turn signal in a directions a couple time. Nothing consistent but it happens.

[wayno]

I have a truck that the brights thing happens every once in a while, I move the lever to signal a right or left turn, and the brights come/flash on, it happens when the headlights are on also, I just don't notice it during the day.

The headlight portion of the combination switch is to touchy, and I don't know what you can do about it because I drive mostly during the day now, so I don't care anymore, but I suspect that something in the switch is to close.

As for your power issues with the turn/stop, I would start changing things till you replace what is bad, I had one combination switch that I could not get the turn signals to work dependably, so I changed the 4 way switch, that didn't fix it, so then I changed the combination switch, everything works now.

The brake lights might not have worked either, but I never got past the turn signal issue part to check to see if the brake lights worked.

[mmitchell57]

What's the combination switch?

[wayno]

What's the combination switch?

 

The combination switch is the switch that operates the turn signals, headlights, and wipers, the horn is also wired though that switch.

I suppose I should have called it the "combination switch assembly".  :hmm:

[datzenmike]

 

 

The big one is the hazard relay, the small is for the turn signals. Both the hazards and turns signals don't work. I flipped them and no love. I tried to see if I was getting juice at the fuse block but I got nothing. Not sure if that's something I'm doing or if it's supposed to be like that. Also did the wiggle the switch thing with no joy. I really don't want to have to pull the dash, but you do what you have to do.

 

Also, on the hazard switch, the green and green/white didn't work in either position. On wire I got action from was the red wire connecting to the green/white which was soldered in w/ the ground. I'm lost at this point.

 

. .

The Blue/Red stripe wire on the 4 way flasher should have power at all times. The fuse to check is the 4th  one over from the front.

 

You already said you replaced or checked it and it was fine. I guess check the fuse holder... you should have 12 volts on one of the terminals. If the fuse is good you should have 12 volts on the Blue/Red stripe wire on the 4 way flasher. Fix this