XRT38

Still no changes since the last up-date. I have functional turn indicators, but not the way they were working, and not the way they are designed to work, and so the front signals work normally with the lights off, but only the front signal lights flash and not together with the side markers, which they should flash alternating from the front park signal lamps to the side markers and back and forth between the two, and that's how all 1990 & up should work and how mine have always worked. That's a distinctive change between the 1989 and 1990 model year. So now with the parks or headlamps on the side marker flash alone and act as the turn indicators, so it's half right, but the front parking/signal lamps still just remain solid and don't flash, and the crazy part of this that they do when the head lights are off, but when you put the headlights or parking lights on then the park/signal front lights don't flash at all. Consequently I bought a continuity probe to check the wiring plug which is spotless and then to begin checking other connections. I am leaning towards the headlamp light switch to be a possible cause as that seems so related. Someone said the front parking indicator lamps are single element bulbs but the only ones listed are 2057 and those are dual element bulbs. It's what's in it and they are fairly new and worked fine till this wonky business started.

Update First thanks for that help. I'll have to take your wiring and see if it crosses over correctly as best I can tell by looking at the images. See this thread & So this evening the parts arrived. I got two new Dorman 3 wire park/turn lamp sockets installed but they are dorman part #85898 (Ford). Fit perfectly but the wire codes are different. It's got a red, white, & black wire. I wired the red to the chassis blue power wire, the black to chassis black, and the brown to the chassis grey wire. https://www.autozone.com/electrical-and-lighting/brake-lamp-socket/p/dorman-light-socket-85898/228423_0_0 Evidently this is right. I also replaced the socket to the side marker light on the left side. I have the right as well but had to stop for the night. Results are the left dash indicator light is no longer lit when the lights are on. The right side dash indicator is still lit. I assume the side marker socket on the right is a problem. I'll know tomorrow when I get that soldered in. With the headlights/parks off the signals work, but do not alternate flashing, which is what the 1990 & up version do, mine always did. However at least now the parks do flash but only when the lights are out. When you turn the headlamps or parks on they stop. So I'm hopeful that the problem goes to the side marker socket on the right side. The most obvious issue was that when I stripped off some insulation on the Black Ground wire from the chassis it was corroded and I cleaning it up and soldered the replacement sockets wire to wire. The parking signal lights are now about 3X's brighter than they had been and left side marker light is also brighter than the one on the right (passenger side) that I haven't replaced yet. We will see tomorrow how or if that does anything. I also have yet to get the Right rear tail light plugs de-gunked and repacked. They light and the signals & brake lights work but there's no doubt that cleaning those and repacking them some fresh dielectric grease is necessary after having done that on the driver side. I strongly recommend doing that. That factory bulb grease was getting pretty stiff and offering little protection from rust. So that's the deal for the moment. Small amount of headway but some progress.

I'll have to take your wiring and see if it crosses over correctly as best I can tell by looking at the images. I got two new Dorman 3 wire park/turn lamp sockets installed but they are dorman part #85898 (Ford). Fit perfectly but the wire codes are different. It's got a red, white, & black wire. I wired the red to the chassis blue power wire, the black to chassis black, and the brown to the chassis grey wire. https://www.autozone.com/electrical-and-lighting/brake-lamp-socket/p/dorman-light-socket-85898/228423_0_0 Evidently this is right.

Thanks everyone for your input. I will update when I get the parts to replace the sockets up front. I am strongly leaning towards believing that one of the marker sockets has lost it's ground is being grounded through the power to the other side marker bulb & evidently what that does is feed back to light interior dash marker/signal lights when you apply the parks or headlights. I don't think the turn signal sockets are bad but I'm going to replace the both of them and then do an autopsy on them to check.

Thanks for the effort. I fixed an original to better than new operation. Just use a soldering iron to melt the ground tunnel open and then cut the wire and solder a new chunk of scrap tin cut to fit to the wire, insert and then remelt the old plastic back over the hole. It's worked fine ever since. You should really stuff those full of dielectric grease to prevent corrosion. Anyway's I did order a replacement socket and will put those in both parking/turn signals. Also Dorman Light Socket 85898 is an exact OEM replacement, even though it say's it isn't. Dorman part https://www.autozone.com/electrical-and-lighting/brake-lamp-socket/p/dorman-light-socket-85898/228423_0_0 is an exact OEM fit. I had one new and tested it yesterday in the lens. It's exactly the same fit including the too long back that makes stuffing it in stupidly un-necessarily difficult, but that's exactly how the factory socket fit.

Reply: I know man, it's the craziest wiring system but probably much simpler than todays nightmare machines. I will update when the new parts to replace the side marker and front signal sockets arrive in about a week. I did take out the left rear signal and cleaned the ground, then disassembled the turn indicator sockets. Those are designed to come apart BTW, then cleaned out masses of hard old dielectric grease and repacked with new dielectric. Rear lights seem fine but I have to do the same to the passenger side now.

Also what's this silver cube thing under the signal flasher in this picture? I unplugged it and cleaned the terminals. Not that any were bad to speak of but I've no clue what it is In the truck it's on the bottom of the fuse panel

Thanks, that was fast.. It's a 1990, or so they claimed when I bought it in Jan of 1990. I've often sort of wondered about whether it really is a 1990 model year. Anyways that's what it's registered as. By socket are you talking about the light bulb sockets & not a wiring socket? All the wiring sockets look good & clean and like those shown in the thread on electrical sockets. I cut the one on the drivers side open to replace the rusted out & broken ground with a soldering iron and then re-welded the plastic back together. I also bought a replacement socket in case # Dorman #85898 is an exact replacement even if they claim it isn't. Just checked today and it fits perfectly and looks exactly the same as original equipment. Pretty sure they are both working normally and aren't rusted out and not making ground. "As for the flashing marker lights, if I recall correctly, the ground for that light to flash is shared somewhere in the turn signal circuit and I think it uses the filament for the flash as a ground until the flash turns on and thus the marker shuts off and turns on opposite to the turn signal." That's the thing about this, the parking lights don't flash at all. They will turn on with the parking light setting and with the headlights but won't flash. Meanwhile the markers do. I put a test light on the plugin up by the airbox that feeds the wiring harness for the lights and there's a grey wire which flashes the test light so I know it's getting a pulsed feed to the harness. I replaced both marker light bulbs *194 the bayonet type so they are fine. I am beginning to wonder if those sockets are gonner's

Any ideas here about what might be going on will be appreciated. What I have right now is both inside dash signal indicators stay lit when the park or headlights are turned on. The outside turn signals only flash on the side marker lights and not the park signal lights at any time, but both parking/signal lights will light and stay lit when they are turned on. The way this should work is that the side and front park/signal lamps alternate flashing & of course the interior dash indicators aren't lit all the time with the lights on. * Notre> From 1990 on these should alternate between each other. That is, the park signal lights should flash & go out and then the side marker flashes and so the it all repeats. 89 & earlier don't alternate is my understanding. The markers stay solid and only the park/signal light flashes. In trying to get this sorted out I had the signal flasher go out so I replaced it with a heavy duty flasher and that's how I got the side markers working as turn signals, but the instrument signal lights on the dash continue to stay lit whenever the headlights or parks are turned on. Again, the front signal/park lights don't flash at all and stay solid. So somehow or somewhere there must be a relay or flasher between these two lights for them to alternate flashing? Hopefully that makes sense. I know the 4 way flasher works, I know the signal flasher works, all the lights work normally other than the dash signal lights staying on with power to the park & headlights, & of course the parking/signal lamps aren't flashing but are lit. I don't grok how this thing is supposed to alternate flashing without some sort of relay grounding out the circuits alternately~

I've been running mine without a thermostat for like years. A tad cool in the winter so you might put one in for that but these trucks just don't have enough cooling to begin with & that high pressure overflow always leaks. Had that thing blow out due to overheating with a thermostat. Frankly I'd just leave it out unless you need heat for winter.

I bought my 1990 LB Comanche new when I in my early 30's. I had the motor rebuilt about 15 years ago when it wouldn't quite pass emissions with 360K on it. I'm guessing I now have about 500K on the whole. They had to bore it out 60 thousands at the time because the cylinders were oval. Hopefully will last me till I pass on to the great junkyard in the sky. I just changed the oil & filter this evening on it. I always try to change it about every 2,500 to 3,000 miles. Nothing special, just 10/40 or thereabouts with about a quart of Royal Purple Synthetic added to help keep it clean.

Follow up on this topic. First off I was confident that the recommended repair would likely solve the problem. This was reinforced by understanding that the back up lights which had just recently stopped working were directly related. All evidence indicated the NSS was the culprit. I managed to remove the NSS with only minor complications. This was primarily thanks to the built in drive train auto lubrication system, which is an advanced feature of self loosening valve cover bolts. Consequently the entire transmission has a fine rust preventive oil coating and that enabled the NSS to be gently, very gently, pulled outwards with a slight side to side wriggling on it. The biggest problem are the Zip Ties that attach the cable to another cable deep inside the transmission tunnel and up high where you have almost zero working room. How anyone manages to cut those without damaging the cable with cutters is beyond me. The Zip Ties on the wiring cable can be almost impossible to remove, but the trick to these is get a soldering iron and then melt those in half, which is how I rather quickly removed that impediment to success. The outer large wiper bolt was loose, and the lock tabs that supposedly secure it were bent outwards and one was twisted. They were not engaging the wiper arm nut much. Quite frankly I'm surprised mine was still attached. This meant that the wiper arm inside of the NSS wasn't being pulled against the contacts inside. There was almost no tension being put on the wiper arm. Opening the NSS and cleaning. Next, when I removed and opened the NSS there was no noticeable spring action on the wiper arms teeny tiny copper wipers. The grease inside was hard and glue like. The tiny springs were so gummed up they weren't providing any noticeable spring action to the wiper contacts. * Caution here for any future readers: The springs that push on the wiper arm's contacts are extremely small. Remove the NSS and put it on a table or area which is clear and clean so that you do not lose the springs. Work slowly and carefully when removing those tiny copper contacts that the springs reside under. If disaster should happen and you somehow lose a spring you could improvise with a cut down spring robbed from a disposable lighter. I bought the recommeded CRC electrical contact cleaner and some dielectric light bulb grease and then cleaned and relubricated the inside of the NSS. This restored the spring action to the wiper contacts and then reassembled the NSS for reinstallation. Patience is needed because it looked to me like the shaft coming out of the transmission that controls the NSS is plastic. You do not want to break that obviously. I might be wrong and it may be metal but mine looked like it was plastic. Long story short, after a number of times monkeying around with the NSS's position I finally managed to get the wiper arm shaft aligned with it's hole along with the top bolt hole. The top bolt that secures the NSS to the transmission seemed to be stripping so I stopped putting torque on the bolt. Just be careful you don't strip it is what I'm saying. It's only an aluminum thread that the bolt goes in to. Possibly vibration over a half million miles made this marginal. Once everything was reconnected I then put the selector in reverse as directed and turned the key to on and checked the rear back up lights. Next, I then placed the drive selector to park and started the engine. I then shut it off, restarted in neutral, shut it off, and then tried to start it in drive and the low ranges which it did not do. I deemed the repair a complete success and went inside to file this report. My deep thanks to the Comanche Club for the help.

1990 2 wheel drive long bed. I had the motor rebuilt at 360 thousand miles about 12 years ago. It's the same original motor but they had to bore it 60 thousands over to take the oval out of the cylinder tubes. I have to guess but I think it must have at least 500K on the motor. I bought it new 32 years ago this January. It was on sale for $9,999 at the time. I'm 66 years old now. We both look well used.