Wiring Problem(s)

[Yogi05]

2008 Foton TB504
Tractor has factory cab so switches etc. are not exposed directly to weather.

Front work lights and headlights work intermittently.
Left side signal and hazards not at all.
Right side signal and hazards work but the relay buzzes unless you press it in firmly.

I have been taking this in sections but without a specific schematic it's the Devil's work.
I have the dash removed and harnesses available. I suspect I have multiple corroded connectors.

I got a 2 pin flasher as a replacement for the 3 pin. It works OK but only the right side lights work (as has been the case).
With a test light there is a solid battery feed to the relay, but with the flasher (2 or 3 pin) installed
there is a very low light from the test light on the "load" wire (the wire out of the flasher to the switches) when the haz or signal switches are off.
This to me indicates a power bleed.

I figure I'm looking for one or more corroded connectors, so I started with the right rear tail light lens because
A corroded wire fell off that one already while poking at it.

My mystery (or mistake)

I took the lens out, cut the corroded screws holding the cover on the back so I could access sockets and checked for corrosion.
One socket is a touch rusty along the sides but the isolator for the center contact is clean.
Using an OHM meter I checked all the wires in the 3 sockets.
I touched the meter to the ground wire, (which is spliced together from all 3 sockets) and the other lead to each individual positive wire.
It was OK.
Then I touched the meter lead to one of the positive wires and the other lead to each of the other positive wires. This showed continuity
between the blue, red and yellow wires with the bulbs in.
I even installed one bulb at a time and checked just to make sure a bulb didn't have a shorted filament I couldn't see.

To me this should not be. It is essentially telling me all the wires from the center contact in each socket are joined. This could be my
mistake and normal, so I stand to be informed. This was all done on a bench with no battery power. Just an OHM meter.

A specific schematic would make this all easier. I could actually follow the flow. The wires change color from one side of a connector to the other on this machine.
Very frustrating.

Appreciate any help.

 

[Tinhack]

Unless copied or manufactured under a known design, Chinese electrical products are far from reliable. I sure wouldn't assume the switches are good because they aren't exposed to weather. They design and build to the least costly manufacturing principle. They use plated (sometimes) steel for contacts which leads to rust. Even their light sockets are questionable. I've worked on imported scooters and motorcycles and found loose bulbs inside housings. They just fall apart and the insulation is typically a layer of vinyl material--Most likely scraps from another industry. When this material is crushed by rivets, the material splits and causes shorts. I also found their wire has substandard insulation and will short to other wires in a harness at bends or compression. You bought one of the cheapest tractors on the planet. Don't expect quality manufacturing.

If I were you, I'd start with the power feed wire(s) and meter every junction under separate/isolated power. Sometimes they follow a wiring diagram but don't count on it. Mark or tape each wire as you follow it to a destination. It's not going to be easy but at least it's not a car or truck with hundreds of circuits.

Good luck!

 

[Yogi05]

Thanks Tinhack

I didn't buy this tractor, it was given to me. And not because of electrical problems. The previous owner happily ran it without lights working. He had three of them, I needed one, he gave it to me with a FEL and snow blower to boot.

That said, I am aware the connectors and switches are suspect and if I want lights to work properly I may have to replace housings, switches and who knows what else.

In the meantime I was looking for confirmation or correction on this........

Using an OHM meter I checked all the wires in the 3 sockets.
I touched the meter to the ground wire, (which is spliced together from all 3 sockets) and the other lead to each individual positive wire.
It was OK.
Then I touched the meter lead to one of the positive wires and the other lead to each of the other positive wires. This showed continuity
between the blue, red and yellow wires with the bulbs in.
I even installed one bulb at a time and checked just to make sure a bulb didn't have a shorted filament I couldn't see.

To me this should not be. It is essentially telling me all the wires from the center contact in each socket are joined. This could be my
mistake and normal, so I stand to be informed. This was all done on a bench with no battery power. Just an OHM meter.

 

[piper184]

If the bulbs involved have more than one filament you should remove the bulb for testing. The filaments likely have a common ground and therefore can "backfeed" from one conductor to another. In other words, there is your short. Even a bulb on the other side of the tractor can cause this if they are on the same circuit. Your continuity flowed down the positive wire, through the bulb to ground, through the ground to the next bulb, through the filament and back out through the positive wire of the other bulb. When looking for shorts, remove the bulbs.

Since you have known corrosion issues, I would start with the grounds. Check every socket (not just the wire) back to battery. Take a resistance reading. Same with the power wires, check voltages everywhere you have access. Always check your grounds, then check them again. Funky connections make electricity go where you don't expect it to. (I am currently trying to find out why there is voltage traveling from my shop to the house via the buried copper propane line. Noticed a small spark while changing out the tank regulator, NOT good! Most likely a bad connection or a failing buried neutral wire) Did I mention, check your grounds? When you find a ground wire bolted to the frame or engine, if you see more than a few ohms of resistance back to battery negative, remove the bolt clean and shine the connection and put it back together. Start with both ends of the battery cables. For lights, check in wheel wells, a common place for ground to frame and a really poor choice too!

You are correct, you need a schematic otherwise you have no idea where things might be tied together unless you follow every wire. Not impossible but as you say, the devil's work. You might want to make your own schematic. Take a tail light assembly and draw out the wires from socket to harness connector. You can make notes about wire colors and put one item on a page. Label the harness connectors on the tractor and your drawings. Tedious for sure but you will gain the information needed. You can work on one circuit at a time as needed.

Use your favorite search engine to see if you can find a schematic. Perhaps someone posted one in a forum or web page somewhere.

 

[Yogi05]

Your continuity flowed down the positive wire, through the bulb to ground, through the ground to the next bulb, through the filament and back out through the positive wire of the other bulb. When looking for shorts, remove the bulbs.

Much to my embarrassment, this is exactly the conclusion I came to once I stared at it enough. Then confirmed with a power source.

Since you have known corrosion issues, I would start with the grounds. Check every socket (not just the wire) back to battery. Take a resistance reading. Same with the power wires, check voltages everywhere you have access. Always check your grounds, then check them again. Funky connections make electricity go where you don't expect it to.

I'm going to cut out all the "outdoors" connectors at some point. For tail lights, work lights. No more corroded connectors.
I cleaned the battery to chassis ground already, and yesterday I found a medium weight ground wire inside the lower dash that had fallen down. It was not connected to anything. I confirmed it was a ground and connected it to a clean location. The eyelet didn't have any marks from previous installation that I could see, but that doesn't mean much). Haven't found any other (body) grounds yet.

(I am currently trying to find out why there is voltage traveling from my shop to the house via the buried copper propane line. Noticed a small spark while changing out the tank regulator, NOT good!)

Friggin' YIKES !!! Hope you find that one quick!

Use your favorite search engine to see if you can find a schematic. Perhaps someone posted one in a forum or web page somewhere.

I have been looking since before I even got this thing home. No luck. And it would have to be year specific when it's wiring. The newer models of the same machine are very different but I can't find any schematics for those either.

My next goal is to find out why there is a bleed at my flasher relay with the ign key on.
Power in, through the flasher, and the wire that goes out from the flasher to the switch(es) dimly lights my test light. If you turn the signals or hazards on, there is power off and on in that wire, no dim light between flashes.

That wire goes directly from the flasher to the switches so when I got home from night shift this morning I confirmed the dim tester, then pulled the hazard switch, and the signal switch individually. No change in the dimly lit test light.


P.S. Hoping for some help with this too.
P.S.S. I hoping this isn't another embarrassing discovery

 

[piper184]

Turn signal wiring can be, shall we say Messy. Lots of different ways to do it. You can find some of them laid out here:
turn signal flasher wiring schematic at DuckDuckGo

Do your brake lights and turn signals share the same filament in the rear bulb like they do in American made cars or are the turn signals in their own single filament bulb as in most other countries? I am betting separate bulbs, but had to ask.

I've seen turn signal relays that were "hot" with the key on and the switch provided the ground to activate the lights. Think dome light switch in an older car door post
I've also seen them where the switch provided the "hot" to the relay and the switch got it's power through the key switch.

You wouldn't believe the backwoods engineering I did to make the signals, emergency, dash indicators and switch backlights all work properly when I replaced the switches on my Jinma. The wiring under the dash still confuses me, and I did it! Actually I wanted the backlights in the switches to flash with the bulbs and used the diodes in an old bridge rectifier to stop the backflow from one switch to another.

Your dimly lit test lamp may be a backflow from another circuit. Pull the relay from its socket and test each plug for voltage with the keyswitch off and then again with it on. Then check continuity to ground at each plug. This may help you sort out how the flasher operates. Another approach would be to remove all the turn signal bulbs from their sockets and check again to see if the test light still lights up dim with the key on. The dim light is most likely an indication of a bad ground or possibly a bad switch.

 

[Yogi05]

Thanks Piper

I had 10 minutes this morning after work and did another visual.
Found the left side tail light plug wouldn't come apart and a wire broke off at the touch of it.
Cut the connector out and had to destroy it to get it apart.
No surprise, it was a ball of corrosion.

Next step is to refresh any connectors I can't get apart, either by soldering wire direct, or replacement connectors (preferred).
I'll check the backflow problem on the way to find new connectors. Hopefully the second corroded connector is the cause.

Either way I'm making progress of a sort.
(Piper, hope you're keeping tabs on this thread. You've been helpful so far and I figure I'll likely need more advice on this).

 

[piper184]

That is some ugly stuff right there...
Go to your friendly local automotive parts store and pick a style of connector you like. Weatherproof preferred but may not be an option. In any case di-electric grease is your friend on re-assembly. Also either Bo-shield (sp?) or ACF-50 are great products. I use ACF-50 because that is what is available. I put a few drops on the open end of every wire I can get too every year or so. It soaks in by capillary action and claims to stop corrosion from getting worse and to stop it from starting in the first place.
If you must splice onto a wire to replace damaged sections or to increase the length I recommend crimp on butt splice connectors that have the heat shrink built in. It has an internal layer that really helps to seal the wire insulation to the connector. They are more expensive but in this application, well worth the price.
Keep in mind that the factory wire may not actually be the size it is supposed to be. When trying to connect to "real" wire you may find that the factory stuff will not crimp tightly in the connector. When this happens a little trick I use is to strip twice as much insulation as needed and fold the exposed wire in half to bulk up the volume in the connector. Try to physically strain relief the connector so that the wires are not vibration stressed in or at the edge of the connector. Sometimes impossible to do, but when you can, you will reap the rewards in fewer future breaks.
Good luck and keep us posted.
I get automatic announcements when new posts are made to this thread.

 

[Yogi05]

According to the internet, and a phone call or two yesterday, connectors are rare in my area but they seemed to think I was talking vehicle specific. Of course, I don't care what the connector looks like. I'll visit a friends shop on the way to the stores and see if he has any or an old harness I can clip. If nothing is available I may use flat trailer harness connectors and weather seal the hell out of them.
i was surprised to see di-electric silicone (paste, not RTV type) doesn't seem available either but I'm sure once I get to a parts store they'll have some.
If I end up going without connectors I will solder directly and use shrink tube (heat shrink). I have never trusted butt connectors or crimps.

Thanks again for the help.

 

[piper184]

Connectors and crimpers come in both good quality and poor quality. Getting the good stuff and and using the proper technique is the other side of the choose the proper location coin.
Solder provides the superior electrical connection, but it can lead to broken wires at the end of the solder flow if used in a high vibration location unless properly strain relieved as well as properly sealed. I use all items and techniques as the situation demands.
Surprised about the di-electric, I'm sure you'll find some. Much to the demise of the the modern DIY, many parts clerks can't look anything up without make, model and year. Their systems just aren't designed for that. The new clerks don't get properly trained by the previous generation. Actually, that is a societal problem that extends far beyond the auto parts counter.
You may have better luck finding connectors online at someplace like Digi-Key or Mouser.