Unbelievable Turn Signal Issues

[Ellie Niner]

Okay. First thing is to bin those little amber lights and replace them with something proper. It appears that they shorted the turn and parking light wires together since those lights only have two wires... so that will cause all of the tail lights and dash lights to flash with any of the turn signals with the headlights off, and nothing to flash at all with headlights on. You'll need dual filament bulbs like 1157 or 2057 (stick with incandescent at least until you have your problems sorted). That flasher socket is fried worse than I expected- I would check for melted wiring behind it... melted wiring could be could be how your fuel pump got shorted into the turn signal circuit. I'm presuming your fuel pump doesn't run when you step on the brake? If no, it's confined to your right front turn signal (dark blue wire). The other wire colors are light blue for left front turn, brown for tail/park, and black for ground.

You'll probably need to hit wrecking yards for that fuse panel, and I tend to snip and solder sections of wire and terminals from wrecking yard vehicles too.

 

[atvjoey]

Okay. First thing is to bin those little amber lights and replace them with something proper. It appears that they shorted the turn and parking light wires together since those lights only have two wires... so that will cause all of the tail lights and dash lights to flash with any of the turn signals with the headlights off, and nothing to flash at all with headlights on. You'll need dual filament bulbs like 1157 or 2057 (stick with incandescent at least until you have your problems sorted). That flasher socket is fried worse than I expected- I would check for melted wiring behind it... melted wiring could be could be how your fuel pump got shorted into the turn signal circuit. I'm presuming your fuel pump doesn't run when you step on the brake? If no, it's confined to your right front turn signal (dark blue wire). The other wire colors are light blue for left front turn, brown for tail/park, and black for ground.

You'll probably need to hit wrecking yards for that fuse panel, and I tend to snip and solder sections of wire and terminals from wrecking yard vehicles too.

This is great information I will look into that tomorrow morning. Could you clarify to me the wiring that you see that's shorted/spliced so I can remedy that problem? Thank you

 

[Ellie Niner]

Could you clarify to me the wiring that you see that's shorted/spliced so I can remedy that problem?

Yes.
-Separate the light blue wire from the brown wire on the left side.
-Separate the dark blue wire from the brown wire on the right.
-The brown is for the parking lights, and blues are for turn signals. Doing this will at stop all of the dash and tail lights from flashing with the turn signals... and allow turn signals to flash when headlights are on. The dash turn indicators may glow dimly when headlights are on, but we'll fix that later...

 

[AuroraGirl]

i guess, my gut instinct is to say if they melted a hazzard can prongs and installed those signals... there(?????? wHY???) then you have to assume that nothing wiring is safe on this truck and I almost thing a drop of the column is in order to get a good view of that connector, get closer to the fuse box and inspect it for other damages or tampering. hows the bulkhead look in engine bay. Also, the fuel tank switcher.. unless an 87 has switched ignition for the pumps shouldnt that run all on its own circuit. off live? If it is switched for the fuel pumps, then all this to me points to either wiring at the ignition switch, which would be the overarching power source for a lot of this stuff, not much for relays except horn and stuff. past that, id be looking at harness integrity, removing any non stock things in the harness at various points. blowing the fuse, after some time, is concerning because the current demand shouldnt be changing, unless its got a real bad connection with a lot of resistance making heat and only getting worse, drawing more than the fuse is rated for once it gets there. but with those cheap, numerous add on leds, hard to say ya know.

i vote column pull and get real good looks of the fuse box, insdie behind , the wiring t oand around it, maybe look for a relay wired in for god knows what reason. He certainly didnt know what he was doing, so maybe trying to wrap my head around it is a useless effort.. lol

 

[atvjoey]

Update Time:

To address AuroraGirl, yes none of the wiring gives me hope and I am doing a column rebuild when the parts come in so that should show more of the situation. I worked on the truck today and ut out those front turn signals. This stopped all of my problems essentially but that doesn't mean it's solved. The directionals all work when they are supposed to (except the fronts obviously) but like EllieNiner said there is a faint glow. The fuel pump no longer turns on when I flip the right directional but I still have not found the cause so that would lead me to believe when I wire in new lights the problem will return (Somebody correct me if I may be wrong). Anybody know where the turn signal harness might meet with any fuel pump wiring? I also dropped the hazard panel and there is no damage to the wiring behind the hazard flasher can, just the plastic around it which does seem strange.

 

[Ellie Niner]

The dash indicator glow is from the front side markers feeding back through the green dash indicators. It's a function of how they're wired to flash with the turn signals, and those will go out as soon as you install correct front turn signals.

As far as the fuel pump thing... that's a bit of voodoo I'm not privy to, as I own no trucks newer than 1986. If the fuel pump isn't "blinking" with your turn signal, you might have lucked out. I could only suggest tracing your dark blue turn signal wire from the switch to see if it has melted into any other wires along the way. Since the fuel pump isn't coming on with your brake lights, it's probably not going to be the wire to your right brake/turn, which is the only one I can think of that *might* run near the fuel pump wiring. The RR turn wire is dark green.

 

[AuroraGirl]

Update Time:

To address AuroraGirl, yes none of the wiring gives me hope and I am doing a column rebuild when the parts come in so that should show more of the situation. I worked on the truck today and ut out those front turn signals. This stopped all of my problems essentially but that doesn't mean it's solved. The directionals all work when they are supposed to (except the fronts obviously) but like EllieNiner said there is a faint glow. The fuel pump no longer turns on when I flip the right directional but I still have not found the cause so that would lead me to believe when I wire in new lights the problem will return (Somebody correct me if I may be wrong). Anybody know where the turn signal harness might meet with any fuel pump wiring? I also dropped the hazard panel and there is no damage to the wiring behind the hazard flasher can, just the plastic around it which does seem strange.

if you had a round eye i would offer to sell you a forward light harness since i have a couple, but you have a different harness i am sure.and if you arent already, headlight switches get old and are known to be problematic so if you were to throw one at it, it wouldnt be unwise and would allow you to see if that has been a factor.

so it looks like there is a firewall mounted relay that takes key-on juice from pcm and primes pumps, then a oil pressure switch that looks to see oil pressure and once it does, will then re-enable the relay, so when cranking, and the fuel pump will run. the switch on dash flips power/grounds. each sender should have a grand tab connector thing, i would check this for certain. that would prob ground to chassis which means it would share a ground path as rear signals prob
also, i did some research. SON, can you please tell us all your engine bay ground straps to-froms or show us? Your ECM has a ground on the rear of the engine to the head. this ground must have nothing else chaining off or around it The intake is aluminum, yes? You should have a ground strap on the rear intake bolt to the FIREWALL of the cab. The Battery should cable to the cylinder head,to what I am reading. You should also have a ground from the passenger fender to the the cylinder head
there are three grounds one could add to potentially improve the system, but you should only consider the first one as a "try it" thing:
1. small ground strap from the intake manifold to a unused spot on the engine block or head , maybe near the PCM ground but not over it or under it.
2. alternator case to battery
3. fender or core support to the battery

those last two are more future/overall ideas that often dont hurt, but they arent likely at all applicable to your fixing your current problem. the first one in that list would only be the case if your aluminum intake is for some reason isolated from the engine. @bucket did you by chance say something long ago about the intake being weirdly isolated and that caused some freak issues?

from what i gather, the issues you are having can be caused by the PCM ground possibly mislocated and chassis ground return to battery being incomplete from bad cable or moved. Your chassis ground return is important, and that is why there is two engine to chasis and the one from battery to engine is supposed to be in good shape and the post in clean condition. basically your lighting was messed with to a weird degree, its not un heard of that the grounds were molested. ohm meter should be used to check stuff if you knonww how.

 

[bucket]

I don't recall anything about an aluminum intake being isolated.

With that melted fuse block, it's highly likely that there's other melted wires that are yet to be discovered.

 

[AuroraGirl]

I don't recall anything about an aluminum intake being isolated.

With that melted fuse block, it's highly likely that there's other melted wires that are yet to be discovered.

hmm, im gonna make one more desparate mention then. @Vbb199 you work with tbi a lot, didnt you one day ave a discovery about the intake wasnt grounding and that was causing headache? I have heard that somewhere over a year ago lol

 

[atvjoey]

if you had a round eye i would offer to sell you a forward light harness since i have a couple, but you have a different harness i am sure.and if you arent already, headlight switches get old and are known to be problematic so if you were to throw one at it, it wouldnt be unwise and would allow you to see if that has been a factor.

so it looks like there is a firewall mounted relay that takes key-on juice from pcm and primes pumps, then a oil pressure switch that looks to see oil pressure and once it does, will then re-enable the relay, so when cranking, and the fuel pump will run. the switch on dash flips power/grounds. each sender should have a grand tab connector thing, i would check this for certain. that would prob ground to chassis which means it would share a ground path as rear signals prob
also, i did some research. SON, can you please tell us all your engine bay ground straps to-froms or show us? Your ECM has a ground on the rear of the engine to the head. this ground must have nothing else chaining off or around it The intake is aluminum, yes? You should have a ground strap on the rear intake bolt to the FIREWALL of the cab. The Battery should cable to the cylinder head,to what I am reading. You should also have a ground from the passenger fender to the the cylinder head
there are three grounds one could add to potentially improve the system, but you should only consider the first one as a "try it" thing:
1. small ground strap from the intake manifold to a unused spot on the engine block or head , maybe near the PCM ground but not over it or under it.
2. alternator case to battery
3. fender or core support to the battery

those last two are more future/overall ideas that often dont hurt, but they arent likely at all applicable to your fixing your current problem. the first one in that list would only be the case if your aluminum intake is for some reason isolated from the engine. @bucket did you by chance say something long ago about the intake being weirdly isolated and that caused some freak issues?

from what i gather, the issues you are having can be caused by the PCM ground possibly mislocated and chassis ground return to battery being incomplete from bad cable or moved. Your chassis ground return is important, and that is why there is two engine to chasis and the one from battery to engine is supposed to be in good shape and the post in clean condition. basically your lighting was messed with to a weird degree, its not un heard of that the grounds were molested. ohm meter should be used to check stuff if you knonww how.

This is some great information I will look at all the connections and make sure all the grounds are properly routed. So far I have a front turn signal/parklight harness and lights coming in on Thursday that I will wire up then. I have also ripped the column apart and replaced basically all of the switches except the wiper switch. The turn signal switch had some exposed frayed wires but I'm not convinced that was the problem yet. Once I put the column back together and wire in the new lights I will have a better idea of what is going on I think. Unfortunately, I am also in the middle of a transmission job since the person before me swapped a Muncie m20 into it using a truck bellhousing without the adapter ring so I have to track one of those down. This truck is a serious Frankenstein build.

 

[AuroraGirl]

This is some great information I will look at all the connections and make sure all the grounds are properly routed. So far I have a front turn signal/parklight harness and lights coming in on Thursday that I will wire up then. I have also ripped the column apart and replaced basically all of the switches except the wiper switch. The turn signal switch had some exposed frayed wires but I'm not convinced that was the problem yet. Once I put the column back together and wire in the new lights I will have a better idea of what is going on I think. Unfortunately, I am also in the middle of a transmission job since the person before me swapped a Muncie m20 into it using a truck bellhousing without the adapter ring so I have to track one of those down. This truck is a serious Frankenstein build.

a muncie m20 o:
how do you do that without adapter and what is adapter ring
i have a unit from a chevy monza which i think means m21 but its associated parts should exists somehwere in my shed. i think. it looks like it may have been an auction thing too so hard to say.

Its likely a saginaw, right? since i tried to say I have something maybe lol

 

[atvjoey]

a muncie m20 o:
how do you do that without adapter and what is adapter ring
i have a unit from a chevy monza which i think means m21 but its associated parts should exists somehwere in my shed. i think. it looks like it may have been an auction thing too so hard to say.

Its likely a saginaw, right? since i tried to say I have something maybe lol

Basically, this truck had someone swap in a manual clutch linkage into it from an earlier squarebody with a Muncie m20 but used the chevy truck bellhousing which has a larger (5 1/8 IIRC?) bearing retainer hole than a typical car bellhousing (4 11/16) so places make an adapter ring to reduce the size of the hole. Other than that swapping in the trans just means cutting a hole and potentially some driveshaft work. I can't tell from the picture but if it was from a Monza it's probably a Saginaw. Sadly I learned all of this information when my transmission refused to shift anymore after being "brand new" according to the previous owner all because he didn't know what he was doing. He even put the transmission cross-member upside down lol.

 

[AuroraGirl]

Basically, this truck had someone swap in a manual clutch linkage into it from an earlier squarebody with a Muncie m20 but used the chevy truck bellhousing which has a larger (5 1/8 IIRC?) bearing retainer hole than a typical car bellhousing (4 11/16) so places make an adapter ring to reduce the size of the hole. Other than that swapping in the trans just means cutting a hole and potentially some driveshaft work. I can't tell from the picture but if it was from a Monza it's probably a Saginaw. Sadly I learned all of this information when my transmission refused to shift anymore after being "brand new" according to the previous owner all because he didn't know what he was doing. He even put the transmission cross-member upside down lol.

thank you for that tid bit at end lol youre a new favorite person welcome.

goes to show the cream of the crop isnt all sunshine and rainbows like some people but i wouldnt know anything about that

and oh okay

 

[atvjoey]

Pulled a long night trying to get my truck back up and running. On the plus side, my problem is Fixed! On the other hand, I'm not sure exactly what caused it. I wired in brand new OEM turn signals/park lights and replaced the turn signal switch in the column and that seemed to do the trick. I also cleaned up some shady wiring under the dash where someone was using t-taps for unknown wiring. The switch had some frayed wires so I'm thinking that was the problem. The grounds were all fine but they were a little crusty so I wire brushed them for good measure. The only problem I have now is that the hazards don't really work. The dash lights blink slowly and only for a split second and the turn signals don't actually blink. Any ideas? Thanks for the help so far guys

 

[Ellie Niner]

What happens when you turn the hazards on, then step on the brake pedal? You should get all four corners and dash indicators to light steadily. That'll help determine where the problem lies.