Turn Signal Ground Problems

[JerrodNichols]

This is not like every other bad trailer ground wire causing issues post, so please read this if you have any knowledge about this topic. I've posted about this before but to no avail. I've messed with it for a few months here and there but I'm coming back here to look for any extra advice. I have a 2002 Ranger XLT 4.0L. Without my headlights or running lights on, everything works just fine. When I do have any of those on, here is what happens:

Left turn signal is turned on:
Solid front turn signal light, solid slightly brighter rear left light, solid significantly dimmer rear right light.

Right turn signal is turned on:
Normal operation of right front and rear lights, solid slightly brighter rear left light.

Also note that my brake lights do not seem to turn on very bright if my headlights or running lights are already on.

I've become very well versed and understand this is a common issue after reading so many threads on here and other places. I have sanded down ground 103 on the driver's side of the engine compartment and confirmed continuity to battery ground. Cut and capped all trailer wires and confirmed ground continuity from the trailer ground wire back to battery ground. I replaced the bulb and socket for the left front and rear turn signals. I found some resistance in a ground wire from a headlight to battery ground so I replaced that wire and no changes. I have confirmed continuity to ground to battery ground from every headlight, turn signal, running light, and tail light. Looked at a diagram saying that the tail lights ground to ground 203 on the passenger side rocker panel and found that it was broken so I replaced that with a battery ground cable and it did nothing.

Pretty much running out of things to do without just throwing parts and wires at this truck. Does anyone know any special tricks about this? Any other ground spots that this circuit could be failing to ground to? If so where are they? If you need any extra information to figure this out let me know and I will get it for you.

 

[pjtoledo]

what happens when the 4 way flashers are activated?

 

[JerrodNichols]

4 ways work normally without headlights on. With them on, everything is solid bright except the 3rd brake light on the cab turns off. Also found out that the same 3rd brake light turns off when the left turn signal is on with headlights on. I took that apart real quick and disconnected it with no changes. So no bad ground in that light bulb or socket. Also inspected those wires and they look good.

 

[pjtoledo]

disconnect the headlight bulbs, turn them on, what happens with all the other bulbs?
the various ground lines go thru splices and get consolidated before they terminate at the ground screws.
try to find them and pull on the wires. I've had corrosion in them and wires pull out.

 

[Curious Hound]

Do you have the wiring diagrams book for your truck? If so, could you scan or photograph the pertinent pages and post them? The closest thing I have is for 2002 superduties and excursions. Probably close. But not exact.

 

[JerrodNichols]

For pjtoledo: I disconnected every headlight, turn light, corner light, brake light, fog light, and license plate light at the socket one by one until there were no more. Still the same symptoms at the end of that process. So if it is a socket or bulb, it would be on the dash or something like that. I gave a quick look at the wires and didn't find many splice points but the few that I did find I pulled on them and they didn't budge. I will have to give a more thorough look at all of the wire runs over this weekend.


For Curious Hound: I don't have a book unfortunately. The best I could find is a few pages online that I can't really guarantee are correct but it seems pretty accurate and I've used this website before for diagrams for other cars that have been accurate as well so it is a credible source. Here are the 2 pages I do have from there.

Also from the same website is this:
"
G100 engine compartment, LH side, front
G101 engine, front, LH side 3.0L
G101 on starter
G102 engine compartment, LH side, rear
G103 engine compartment, LH side, rear
G104 engine compartment, LH side, front
G105 engine compartment, RH side, rear
G106 engine compartment, rear, top
G200 LH rocker panel
G201 RH rocker panel
G203 RH rocker panel
G204 behind dash panel, LH side
G205 Vehicle floor, left front side
"

Unfortunately they include in that list grounds for every engine so my 4.0 doesn't have all of these. For example, I went under my truck and didn't see any grounds on the RH rocker panel

It says most of the system grounds at G205: "Vehicle floor, left front side". Has anyone every messed with this ground? Hopefully I don't need to pull carpet to check that one, or at least hopefully it isn't difficult to pull it. Thanks for the help and ideas so far, it seems like it's getting narrowed down to some sort of main ground or crimp issue.

 

[RobbieD]

It says most of the system grounds at G205: "Vehicle floor, left front side". Has anyone every messed with this ground? Hopefully I don't need to pull carpet to check that one, or at least hopefully it isn't difficult to pull it.

Looking at the diagram that you posted, G205 does seem to be the biggest common denominator for a lighting problem, suspected grounding issue.

And the symptoms sure do point to a grounding issue.

I think it would be well worth the effort to access G205 and really inspect it.

I'm sorry, but I don't know the later model trucks, so I can't help with any tips on actually getting to it.

Don't give up, and Good Luck!