99 limited - D and L light up at the same time

[Roger.klotz]

99 limited 4wd auto 3.4 290,000k

I’m having a hard time figuring this one out. Here are the symptoms: The gear indicator lights in the cluster for D and L are lighting up at the same time. The transmission feels like it’s in L when in D. The 10a fuse for the gauges blow shortly after this issue presents itself. After the fuse blows, the transmission feels normal in D.

So far I have done a few things to troubleshoot. I found and insulated a slightly exposed green wire under the dash that was tapped for a trailer brake harness. I removed the neutral safety switch, cleaned the contacts, adjusted and installed. I replaced the blue shifter bushings. I replaced the cluster. I replaced an Abs sensor on the front driver side. Installed a scan gauge 2 to check for Stored codes.

After I did all of the above, The issue went away for about a week. I hit a bump this morning and the transmission felt like it shifted into L. At the same time the indicator light for L came on faintly with the D still lit up. I shifted into 2 and drove towards home. I hit another bump and the 10a fuse for the gauges blew. After I lost my gauges, I was able to shift into D and drive home.

Video of issue
99 4Runner Automatic transmission dash indicator light issue - YouTube

 

[phattyduck]

Oh, man... I was going to suggest gauge cluster until I saw that you already replaced it.

What else... the gauge fuse is connected to a bunch of different systems in the car - but issues in most of those would not affect the gear indicator lights.

I'd do a very close inspection of the wiring harness from the neutral safety switch all the way up to the ECU. You might want to open up the ECU and check for burned and/or damaged components.

Try the original gauge cluster and see if the problem happens with a different frequency with that one.

-Charlie

 

[Roger.klotz]

Oh, man... I was going to suggest gauge cluster until I saw that you already replaced it.

What else... the gauge fuse is connected to a bunch of different systems in the car - but issues in most of those would not affect the gear indicator lights.

I'd do a very close inspection of the wiring harness from the neutral safety switch all the way up to the ECU. You might want to open up the ECU and check for burned and/or damaged components.

Try the original gauge cluster and see if the problem happens with a different frequency with that one.

-Charlie

I didn’t think to check the ECU. I’ll take a look and see if anything stands out.
I suspect a short in the the neutrals safety switch, the harness, or connector, but after looking at diagrams in a Haynes manual I’m not sure how to go about testing these things.

I removed the neutral safety switch from the trans and left the harness connected. I laid under the truck and manually turned the thing while a friend watched the gears indicators change. I was not able to recreate the scenario where both D and L light up together. As far as I can tell, the NSS is what determines which light is on in the dash.

 

[Roger.klotz]

Pictures of dash and NSS connector.

 

[Roger.klotz]

I removed the ECU from behind the glove box and nothing stands out on the circuit board.

 

[sleepydad]

I didn’t think to check the ECU. I’ll take a look and see if anything stands out.
I suspect a short in the the neutrals safety switch, the harness, or connector, but after looking at diagrams in a Haynes manual I’m not sure how to go about testing these things.

I removed the neutral safety switch from the trans and left the harness connected. I laid under the truck and manually turned the thing while a friend watched the gears indicators change. I was not able to recreate the scenario where both D and L light up together. As far as I can tell, the NSS is what determines which light is on in the dash.

yikes this might be easy but... sounds like the light green and white red are getting combined.

62 Combination Meter (1999 4Runner)
07 Overall Electrical Wiring Diagram (1999 4Runner).pdf - Google Drive

07 Overall Electrical Wiring Diagram (1999 4Runner)
62 Combination Meter (1999 4Runner).pdf - Google Drive

note: I just went thru a tracking down similar wires myself on a 1998 so it's different but the II1 and II3 are involved over on the passenger side in glove compartment area.

the transmission wires are in with the engine wire-> enters the cabin on the passenger side in that big rubber accordion guy. the combination meter is connected to the body harness thru II1,II3.

all the E9-E11 connectors on the ECU should not have anything to do with it IMO.

there must be some damage to those two wires someplace and it's causing them to combine their signals.

 

[Roger.klotz]

yikes this might be easy but... sounds like the light green and white red are getting combined.

62 Combination Meter (1999 4Runner)
07 Overall Electrical Wiring Diagram (1999 4Runner).pdf - Google Drive

07 Overall Electrical Wiring Diagram (1999 4Runner)
62 Combination Meter (1999 4Runner).pdf - Google Drive

note: I just went thru a tracking down similar wires myself on a 1998 so it's different but the II1 and II3 are involved over on the passenger side in glove compartment area.

the transmission wires are in with the engine wire-> enters the cabin on the passenger side in that big rubber accordion guy. the combination meter is connected to the body harness thru II1,II3.

all the E9-E11 connectors on the ECU should not have anything to do with it IMO.

there must be some damage to those two wires someplace and it's causing them to combine their signals.

Thank you so much! I located the harness/connector from the NSS behind the glove box. Unplugging this connector turns the indicator lights off on the dash. Hopefully the issue is easier to isolate now.

 

[sleepydad]

Thank you so much! I located the harness/connector from the NSS behind the glove box. Unplugging this connector turns the indicator lights off on the dash. Hopefully the issue is easier to isolate now.

yes I would think you could check for continuity in the 2 wires upstream and down stream of that connector? I think. this way it tells if it's engine side wire harness or body harness. either way it's not going to be fun to track that down.

post back I would love to know what is happening here?

 

[Roger.klotz]

I connected a multimeter to each end of the connector behind the glove box and tested continuity between light green and white/red. I also tested light green to ground and white/red to ground. This should tell me if the wires are making contact with each other somewhere right? It’s been awhile since I’ve used a multimeter for more than voltage. If I should be testing a different way please let me know.

Battery is disconnected, NSS is disconnected.
Glove box connector:
Light green to white/red -.4 k ohms
Light green to ground - 5 k ohms
White/red to ground - 14 ohms

Under truck at NSS connector:
White/red to light green - .4K ohms
I ordered a replacement neutral safety switch as well.

Thank you

 

[Roger.klotz]

From what I can see under the truck the light green and white/red wires are across from each other in the connector. I drew squares around the ones I’m referring to. Can anyone confirm this?

The white/red hole looks like it’s melted at some point. I’m wondering if the short is in the connector.

 

[Roger.klotz]

Does anyone know if the engine/trans wiring harness can be replaced without major disassembly of the vehicle?

I need to get this thing back on the road.

Thank you

 

[phattyduck]

Does anyone know if the engine/trans wiring harness can be replaced without major disassembly of the vehicle?

I need to get this thing back on the road.

Thank you

The upper intake manifold has to come off along with the glove compartment, but not much else. The trans wiring will be a pain because the connectors get stuck due to dirt.

I haven't really heard of harness problems though, so that's a long shot.

The odd problems I had that were something like this (though, not the same) turned out to be the flex PCB on the back of the gauge cluster.

-Charlie

 

[Roger.klotz]

The upper intake manifold has to come off along with the glove compartment, but not much else. The trans wiring will be a pain because the connectors get stuck due to dirt.

I haven't really heard of harness problems though, so that's a long shot.

The odd problems I had that were something like this (though, not the same) turned out to be the flex PCB on the back of the gauge cluster.

-Charlie

Thanks for the info. If it comes to replacing the harness, it sounds like something I can handle.
I replaced the cluster first thing after searching the forums but unfortunately the problem is deeper.

 

[gamefreakgc]

Thanks for the info. If it comes to replacing the harness, it sounds like something I can handle.
I replaced the cluster first thing after searching the forums but unfortunately the problem is deeper.

Finding a replacement wiring harness might be harder than it seems. There a several kinds for every model year for 2WD/4WD, CA emission vs Federal emissions, among other things. There is a part number printed on a white tag on the harness itself, I cannot remember exactly where it is though. That's what you'll want to find and match.

 

[sleepydad]

Thanks for the info. If it comes to replacing the harness, it sounds like something I can handle.
I replaced the cluster first thing after searching the forums but unfortunately the problem is deeper.

so you were not able to track down the trouble? or you did and figured out there is damage someplace inside the harness?

I just did it on my 98, and it fixed my issue. truck runs great again.

replaced the starter + engine harness. As [MENTION=139000]phattyduck[/MENTION] indicated you will need to remove the upper,lower intake to unhook the injectors. most of it is pretty straight forward but it took me several hours to get it all off without destroying anything.

also took me a couple of hours to get it all back on and some new intake gaskets along the way.

I got my harness from salvage place in rancho CA

Car-Part.com--Used Auto Parts Market

searched for engine wire wire harness

called the place and neggoated price a little. $250 with shipping to my door.

make sure you get the vin and make sure it's the correct part for you truck. your wire harness should have a part number on it up where it connects to the ECU. should look something like this

<a href="https://imgur.com/dOjPBmS"><img src="https://i.imgur.com/dOjPBmSl.jpg" title="source: imgur.com" /></a>

I think the part your after is

federal = 821213G311
California = 821213G341

California spec is the one for 2x catalytic convert trucks.

you should be able to find something like this one, not sure if this is the correct one but they are out there

2000 Toyota 4Runner Engine Wiring Harness-Stock# 180076

and one more thing... I did have to repair 2x connectors on the salvage harness. not a huge deal but depinning and swapping connectors can be a pain. the salvage guys can be a little angry when they remove things... just how it goes with salvage.

 

[gamefreakgc]

make sure you get the vin and make sure it's the correct part for you truck. your wire harness should have a part number on it up where it connects to the ECU. should look something like this

<a href="https://imgur.com/dOjPBmS"><img src="https://i.imgur.com/dOjPBmSl.jpg" title="source: imgur.com" /></a>

I think the part your after is

federal = 821213G311
California = 821213G341

California spec is the one for 2x catalytic convert trucks.

Thanks for the extra information. I've pulled 6 wire harnesses but never paid attention to where the part number was lol.

 

[sleepydad]

Thanks for the extra information. I've pulled 6 wire harnesses but never paid attention to where the part number was lol.

I have pulled a couple now... but this time I needed a very specific version of it for 1998 with the specs I have. I wish I could have found it local and would have done it myself. I was only able to find 3-4 of them nation wide.

salvage guys are always hulk smash it! I went thru the entire harness and replaced all the gunky parts. 2nd time I have done it and I'm getting pretty good at it. 2x rolls of tesa anti abrasion and new style painless split braided sleeving works out really well.

 

[Roger.klotz]

so you were not able to track down the trouble? or you did and figured out there is damage someplace inside the harness?

I just did it on my 98, and it fixed my issue. truck runs great again.

replaced the starter + engine harness. As [MENTION=139000]phattyduck[/MENTION] indicated you will need to remove the upper,lower intake to unhook the injectors. most of it is pretty straight forward but it took me several hours to get it all off without destroying anything.

also took me a couple of hours to get it all back on and some new intake gaskets along the way.

I got my harness from salvage place in rancho CA

Car-Part.com--Used Auto Parts Market

searched for engine wire wire harness

called the place and neggoated price a little. $250 with shipping to my door.

make sure you get the vin and make sure it's the correct part for you truck. your wire harness should have a part number on it up where it connects to the ECU. should look something like this

<a href="https://imgur.com/dOjPBmS"><img src="https://i.imgur.com/dOjPBmSl.jpg" title="source: imgur.com" /></a>

I think the part your after is

federal = 821213G311
California = 821213G341

California spec is the one for 2x catalytic convert trucks.

you should be able to find something like this one, not sure if this is the correct one but they are out there

2000 Toyota 4Runner Engine Wiring Harness-Stock# 180076

and one more thing... I did have to repair 2x connectors on the salvage harness. not a huge deal but depinning and swapping connectors can be a pain. the salvage guys can be a little angry when they remove things... just how it goes with salvage.

I replaced the neutral safety switch and the issue is still there. I wasn’t able to pinpoint the short, but I believe it’s somewhere in the engine harness based on continuity checks with the multimeter. Thanks for the info on the harness part number. I’ll check near the ECU but if I remember right, there’s no sticker. It looks like the harness has been taped back up with electrical tape near the ECU and in a few other areas. Once I have a replacement harness, I’ll pull the intake manifold and see if I can locate the short.

 

[Roger.klotz]

I found the sticker on the harness and snapped a picture.
Part # is 821213G310A
I'm searching for a replacement now.

 

[Roger.klotz]

I started unplugging the harness from the trans and O2 sensors so I could fish it out and get a better look. I found a few exposed wires near the neutral safety switch connector after peeling back the plastic.