No Right side trailer turn / stop. Need a Cluster

UPDATED 3rd and fixed

right side trailer turn always on
so testing at the 7 pin plug
right side stop turn pin is always on
does not flash with truck, actually stops the truck from flashing

what could it be??? flasher relay





Thanks Pete

 

Bump

 

Did you put a test meter across your truck plug?

 

yes I am testing the truck 7 pin trailer connector.
nothing on the R/S stop turn pin.

 

Pull the trailer light plug on truck and check wire connection.

 

did that. no power to the wire there either. where does the right turn stop wire go after that. gota be a connector corroded between the 7pin and the fuse

 

bump

 

Wiring diagrams are found here.
Ultimate TUNDRA Wiring Diagrams Collection | Toyota Tundra Forum (tundras.com)


There are 10 pages for the trailer brake that includes the plug wiring.
But this isolates your turn signal feed to the plug.

 

Thanks 1lowlife , I have tried to follow the path with the elec dia. Its chinese to me. the wire has power, it just doesn't flash, maybe there's a flasher relay that someone could point me to, truck is a 2021

 

Is it just the plug that doesn't flash or the truck as well?

My 2014 has an electronic flasher relay under the driver's side dash.



I can't find one in the 2021 diagram.
@RainMan_PNW can you help this guy?

 

just the trailer plug, Right side no flash. truck is fine.
The trailer pin also has constant power to that same pin when the key is off. pull the 30amp towing fuse and the power is off.

 

Did you buy truck new or used. Just asking because someone could have modified something.

 

Good point, got it used but old owner was not that guy that mods stuff. I also don't see any evidence of anything that has been messed with, its gotta be an internal relay, Im starting to think inside the cluster as that's where the wiring dia points to next.

 

That's odd.
Even the BATT pin 5 doesn't have power unless the ign is on, but it's a 40 A fuse.
30 A fuse is the tow tail pin 2 that provides tail running/ parking lights
I would think it would only have power when the lights are on.

There should be no power to anything if the parking lights, brake, and turn signals are off.

Did you compare the wires colors on the diagram to your socket and make sure they match up.
@Stumpjumper may be on to something.



One more question;
Is this with the trailer hooked up, or did you test the wires with a DMM?

Same results with the 4 pin connection?
Not sure if the 2021 has both, my 2014 does.

 

yes its the pink wire pin 7 STTR, Key off DMM reads 12.19v same as battery volts.
pin 7 pink goes from the trailer connector 7/4 combo to the combination meter assembly [cluster] there is a box in te diagram that says [IF] maybe internal fuse. branches of that and leads to the 30amp towing fuse. pull that fuse and pin 7 is dead.

Im stating to think there could be a relay in the cluster that is bad.need that diagram

 

I looked all over for a turn signal relay and couldn't find anything for your truck.
As stated my 2014 has a physical electronic relay part, but I couldn't find anything with yours..

Oddly, this issue is only on the trailer plug and stranger only 1 pin..
I'm no mechanic, I'm just a guy that likes to figure stuff out..

If you click in this link on 2016-2021 overall diagrams, it will give you the detailed diagrams for the Multiplex Communication and the Combination Meter Assembly.
But those are WAY over my head..

Ultimate TUNDRA Wiring Diagrams Collection | Toyota Tundra Forum (tundras.com)

 

Well thanks for the help, I did look over the wiring diagram for the cluster, its not showing the detailed circuits on what is for sure a circuit board... unless someone on here can really get into the weeds of that cluster diagram. I think my only option is to take the cluster to a repair place , its 1600 Canadian Pasos here, think its $500 usd maybe i find one on evilbay and give it a shot.

 

Is this only when something is plugged into the trailer socket? Post 11 says "truck is fine" so I'm confused here.

Also need to know - is the light at the trailer ON but not flashing, or OFF and not flashing. Based on the rest of what you are describing, I am picturing it is ON but not flashing - but I want to be sure of that.

Famous last words. He could have just as easily paid someone to install something (aftermarket trailer controller? security system? etc.) and then paid to have it removed before selling - during which either installer or uninstaller could have borked something. Hell - just the number of brand new trucks that arrive in the buyers hands with some dealer-installed GPS tracking device is enough to say it might be something that the original owner didn't even know about.

You won't find detailed circuits for the instrument cluster. 1) it's proprietary, 2) it's got several controllers and ROM units integrated into it along with plenty of PCB, and 3) it's not meant to be a serviced part.
I also wouldn't try to interpret the diagram too much more than the basic understanding that "I/F" appears to indicate some specific internal IO/Control logic - "integrated function" is how I read them but without a technical clarification from Toyota, I don't think you'll ever know for sure.

In the 2018+ trucks, the Instrument Cluster houses all of the "relays" (via transistors) for the turn signal and hazard flashers. In the case of the trailer/towing, it appears that the brake lights themselves are also controlled by the Instrument Cluster (because both are the same wire - "STOP/TURN").

This is correct (or should be). If you follow the yellow wire from the coil of the TOW TAIL Relay back to page 3, you see that it is powered/controlled by the output of the TAIL relay (tail light system), which is powered by the headlight control in the Main Body ECU.

Paraphrasing post 15 for clarity
Trailer turn signal power is fed from the 30A TOW fuse (direct from battery) and routes into the Instrument Cluster (Combination Meter Assembly). Internal logic/controllers route that power to either Left or Right turn signal/stop lamp via the JJ3 (or JJ4) junction connector, then the AJ2 junction connector, and then the RA5 junction connector before terminating at the R18 connector to the rear Trailer Socket.

Based on your assessment that you have constant power at the Right Turn connector at the trailer socket even with the truck off, unless the 30A TOW fuse is pulled, does lend to the possibility that there is something internally wrong with the instrument cluster.

That said, before you go that far, you need to actually chase your wires out and make sure something else isn't going on. We'll work backwards from the back of the truck to the instrument cluster.


Your PINK wire from the trailer socket (Connector R18, Pin 7) routes along the body wiring harness up into junction connector RA5 in the engine bay (pin 6). When you look at that connector, your pink wire will be entering into the top side of the connector (along with all the other wires from that harness).
Unplug that junction connector, and do two things:

1. Use the DMM to check that pink wire for voltage against a body ground. This checks that there isn't another hot wire somewhere along the path between the trailer plug and the first junction connector.
2. Use the DMM to check the corresponding pin on the male side of the junction connector for voltage against the body ground. This will check/confirm that you are still chasing "hot" power from the battery up to that point.

Test these wires by using an appropriate small diameter probe inserted into the back side of the connector (where the wire enters it) until you make contact with the terminal crimp. DO NOT insert probes into the female terminals to test, unless you have exactly-matching sized terminals on a short pigtail of wire. If you push too large of a probe into a terminal, you can stretch it out to the point it won't make correct contact when plugged back in.

Next, we're going to head for Junction Connector AJ2 (Pin 9), located in the passenger kick panel. For the time being leave RA5 unplugged. When you look at the connector, the plug facing the rear of the truck is the one coming from the engine bay (RA5 and others) - your wire is a red one in Pin 9.
Unplug AJ2 and check these things:

1. DMM for voltage from the red wire (from the engine bay) to ground. It should be zero, since you're working with only a short section of wire that should still be unplugged from anything.
2. DMM for voltage from the corresponding pin on the mating connector to ground. This, again, is confirming/chasing that we have errant voltage still present.

Next, we should also check JJ3/JJ4. I think for 2021, all trucks have the Trailer Towing package, so you should be looking at JJ4, and even though the image shows two connectors, I'm 99% sure you'll only find one connector there (both connectors are the exact same shape/layout and only have two pins). I'm pretty sure you'll have to pull the glove box and lower passenger trim to access this connector. As before, leave RA5 and AJ2 unplugged. When you unlplug it, the lower connector should be the one coming from AJ2, but that's not always the case. You can use the DMM to check continuity from JJ4 to AJ2 to be sure.
Then, as before, check:

1. for voltage at the terminal on the wire going to AJ2 - this is super short, but we're still looking to isolate any section that might have a cross-connection
2. for voltage at the terminal on the wire coming from the instrument cluster - looking to confirm we're still seeing the errant voltage.

Finally, you need to pull the instrument cluster. The Hypertech speedometer calibrator instructions are probably the most succinct I have found for this process. While you have the instrument cluster out, make sure to find and write down the FULL part number of your cluster. You will need that if you are going to shop for a replacement - there are a lot of part numbers and even one letter/number different can mean it doesn't work in your truck.
With the Instrument cluster pulled out, but still connected to the wiring harnesses, you need to check one more time that you are getting voltage on Pin 1 of connector J171 (separate 13-pin connector from the main instrument cluster connections - this connector handles all of your turn signals). You can also check voltage on Pin 13 (the TOW fuse source). It would also be a good idea to try connecting ONLY the TOW battery wire from that harness to the instrument cluster and see if you get voltage on the pin that corresponds to the Right Turn/Stop wire output.

Not really sure where to go from there, other than this will help systematically eliminate some other source.
I've also attached an excerpt from the 2015 FSRM specific to Trailer Brake Control. It doesn't specifically address turn signals (and in the 2014-2017 the trailer turn signals route through the flasher relay like lowlife pointed out in his truck).

 

Thank You Rainman and lowlife for tagging you in this thread.
This is exactly what I needed.instructions on diagnosis.

And just to clarify
when I turn the right turn signal on,,, the truck tail light flashes.while flashing I touch the pin in the trailer plug with a 12v test light . the truck tail light stops flashing,but the trailer plug pin stays lit not flashing on the test light, so any voltage draw on the trailer light pin will stop the truck tail light from flashing.voltage is 12.20v at the trailer plug pin, same as the battery, always hot key on or off.
I will get to these connecters and update my findings, asap. again thanks for the help. Pete

 

Does the truck light stay lit or go out?
Also - how many miles on the truck and did you get an extended warranty when you bought it?

 

trucks right turn light goes out/off.turn the signal stock off wait a few seconds and it will work again, touch the trailer plug pin with a test light and it stops and is out again.

91000km or 56500miles, Im in Canada
no extended warranty

 

If the instrument cluster is indeed the problem, you might be able to convince them that it’s part of the 60,000 mile drivetrain warranty… hard to drive without a instrument cluster.

 

Thank you for your time and knowledge to help him out..

 

step one RA5 its unplugged and grey see image.
pink wire, no voltage when unplugged, pin 6 down in the connecter I think that would be the male pin is hot so leave it unplugged and move to step 2

 

AJ2 ? here is a pic of the pass side kick panel, having trouble identifying the connector.

 

disregard AJ2 red wire pin 9 got it,

 

Ok so after working my way threw all related connectors looking for stay voltage or a short I have determined I need a Cluster,

Combination Meter Assy.
Part # TOY 838000CT91KP $1744 cnd here in Ontario Canada from the dealer, if anyone has a line on a used part I would be interested, a US part would have MPH and the Part I need is Km/hr but I would not care if the price was right. Thanks Pete

 

Ebay
Car-part.com maybe

the trick with using a US one is it has to have the same options regarding:
Fuel type (flex/not)
Fuel tank size
Parking sonar (Y/N)

 

Found A cluster
my Part # 838000CT91KP
used Part is # 838000CT90KP

Can anyone tell me what if any the difference is, or a Part # interchange
Thanks Pete

 

Unfortunately, without access to the detailed toyota parts system, no idea. The descriptions from the parts websites are lacking at best, and my experience with the instrument cluster is that a single digit difference could be significant.