Trailer TPMS sensors loose signal

Andrew Best · December 28, 2020

They definitely will not have the correct readying when the trailer is first pugged in. This is another feature that the aftermarket system (TST) I previously used would do that GM's won't! I could pull up next to my trailer and check the tire pressures before a trip. Now I get a reading from when I last parked it. This means it is of no use before a trip.

Mbower2020 · January 15, 2021

Gentleman, I think I found the connectors at Amazon. Gecko50's post got me thinking. Like everyone else I have the same issue with little to no help from GM. I am going to attempt removing the reciever and mounting it on the trailer somewhere and make the extension like was talked about in the post. Connectors are about a month out coming from China. Lookup

Amazon.com: 5 Set 4 Pin 1-967640-1 / 8E0 971 934/968399-1 LPG Converter Automotive Harness Connector Female Male Auto Plug

Time will tell but I think its the best ideal I have heard yet. Be nice to get it working without dropping out.

Amazon.com_ 5 Set 4 Pin 1-967640-1 _ 8E0 971 934_968399-1 LPG Converter Automotive Harness Connector Female Male Auto Plug for VW Audi BMW_ Home Audio & Theater.pdf

Edited January 15, 2021 by Mbower2020

Gecko50 · January 15, 2021

17 hours ago, Mbower2020 said:

Gentleman, I think I found the connectors at Amazon. Gecko50's post got me thinking. Like everyone else I have the same issue with little to no help from GM. I am going to attempt removing the reciever and mounting it on the trailer somewhere and make the extension like was talked about in the post. Connectors are about a month out coming from China. Lookup

Amazon.com: 5 Set 4 Pin 1-967640-1 / 8E0 971 934/968399-1 LPG Converter Automotive Harness Connector Female Male Auto Plug

Time will tell but I think its the best ideal I have heard yet. Be nice to get it working without dropping out.

Amazon.com_ 5 Set 4 Pin 1-967640-1 _ 8E0 971 934_968399-1 LPG Converter Automotive Harness Connector Female Male Auto Plug for VW Audi BMW_ Home Audio & Theater.pdf

Mbower2020, remember the signal pair has to twisted as noted above. Could you email me when you start up the install and lets see if we can work thru it. I have a idea is that initial get a twisted shielded 2 pair wire or at least 1 wire 18 gauge. Then email me at "[email protected]" Lets see what can be accomplished.

Chuck

Mbower2020 · January 17, 2021

Gecko50, no problem I will keep you posted. Connectors are a ways off I expect them around beginning of Apr. As far wiring goes I did see that the GMLAN is a twisted shielded cable. I am currently rounding up the twisted shielded 1PR/22 and the other 2 conductors a 22awg and a 20awg for the ground. This is what you get when you cross GM's wire sizes .5mm/22awg and .75mm/20awg. Reading the repair procedures above I am now concerned about the extended length causing issues. We will see.

Gecko50 · January 18, 2021

20 hours ago, Mbower2020 said:

Gecko50, no problem I will keep you posted. Connectors are a ways off I expect them around beginning of Apr. As far wiring goes I did see that the GMLAN is a twisted shielded cable. I am currently rounding up the twisted shielded 1PR/22 and the other 2 conductors a 22awg and a 20awg for the ground. This is what you get when you cross GM's wire sizes .5mm/22awg and .75mm/20awg. Reading the repair procedures above I am now concerned about the extended length causing issues. We will see.

May I suggest going 1 size up (larger conductor maybe 2 sizes) this would assist in any signal loss for a longer cable run. Another thing if in your / our quest is that make sure you have signal to the 3rd axle. But be careful you maintain signal for the front tires. I was also thinking IF this works, you parallel both modules. This might keep signals spread to outer reaches. By using the male and female allows a quick check on wires. But using both modules by soldering the cables on the existing stock location.

On a different thought, the connectors appear to be used on different vehicles. Is there any chance of obtaining these plugs from them?

Thanks

Chuck.

Andrew Best · January 19, 2021

I've posted these before. I know they are expensive but they are available .I have spoken to connector experts. We use them in our body shop all the time. I don't have the electrical knowledge to know how to wire it correctly so there is not an issue or I would have done so by now. If anyone is successful please post the instructions !

Andy

Andrew Best · February 8, 2021

Just checking to see if anyone has found any information on a repeater for GM's system?

L8T · February 9, 2021

On 1/18/2021 at 12:40 PM, Gecko50 said:

May I suggest going 1 size up (larger conductor maybe 2 sizes) this would assist in any signal loss for a longer cable run. Another thing if in your / our quest is that make sure you have signal to the 3rd axle. But be careful you maintain signal for the front tires. I was also thinking IF this works, you parallel both modules. This might keep signals spread to outer reaches. By using the male and female allows a quick check on wires. But using both modules by soldering the cables on the existing stock location.

On a different thought, the connectors appear to be used on different vehicles. Is there any chance of obtaining these plugs from them?

Thanks

Chuck.

You won’t lose anything with the extra 10-12’ of wire. As Gecko50 said I would just make sure it’s shielded twisted pair wire. CAN network doesn’t like interference.

I don’t know how accessible this module is but if it was somewhat easy to get at and the proper female end of the connector can’t be found I’d splice into the harness before that module and parallel another Deutsch connector into it. Be sure to unplug the truck module though before using the one mounted on the trailer though because it likely won’t work. The end of line resistor need to be in place in one spot only (2 in the network). If it sees more than one resistor it will likely get a CAN network fault and not work.

If the proper ends can be found, it saves splicing into the harness which is much more ideal.

As mentioned though a repeater would be the most ideal solution.

Good luck fellas. Sounds like y’all are in the right track.

Edited February 9, 2021 by L8T

Gecko50 · February 27, 2021

On 1/17/2021 at 3:38 PM, Mbower2020 said:

Gecko50, no problem I will keep you posted. Connectors are a ways off I expect them around beginning of Apr. As far wiring goes I did see that the GMLAN is a twisted shielded cable. I am currently rounding up the twisted shielded 1PR/22 and the other 2 conductors a 22awg and a 20awg for the ground. This is what you get when you cross GM's wire sizes .5mm/22awg and .75mm/20awg. Reading the repair procedures above I am now concerned about the extended length causing issues. We will see.

Hey Mblower have you gotten the cable ends? If by any chance have you checked to make sure it matches the existing cable end and the transmitter. Have you gotten 2 pairs of connectors or 1 set?

Thanks

Chuck

Mbower2020 · February 27, 2021

Chuck got the ends last week. They match perfectly. 5 sets came in the package. I have all the items needed just need the weather to break here on the East Coast so I can give this a go to see what happens. Hope this will work if not only have about 50 bucks invested.

Gecko50 · February 27, 2021

37 minutes ago, Mbower2020 said:

Chuck got the ends last week. They match perfectly. 5 sets came in the package. I have all the items needed just need the weather to break here on the East Coast so I can give this a go to see what happens. Hope this will work if not only have about 50 bucks invested.

Could I buy a complete male and female set with pins etc.? I could get the money to you and you could send them tome us snail mail? My email is [email protected] then you can email me your cell number and I can call you.

Chuck

Mbower2020 · February 27, 2021

Chuck, I really would like to help you out but I am a little reluctant to give out any of my contact information at this time to someone I only know through a forum. Please don't take any offence to this unfortunately its just the age we live in now. You can buy these connectors on Amazon for less than 15 dollars which I posted previously. Shipping took about half of the time that was stated by Amazon.

I have no problem sharing trials and tribulations throughout the process within the forum. I would rather keep it at that level.

Hope you understand and I thank you for your insight and post as well as the others within the forum which has lead me down this path we are taking.

Mike

Gecko50 · March 2, 2021

On 2/9/2021 at 1:04 PM, L8T said:

You won’t lose anything with the extra 10-12’ of wire. As Gecko50 said I would just make sure it’s shielded twisted pair wire. CAN network doesn’t like interference.

I don’t know how accessible this module is but if it was somewhat easy to get at and the proper female end of the connector can’t be found I’d splice into the harness before that module and parallel another Deutsch connector into it. Be sure to unplug the truck module though before using the one mounted on the trailer though because it likely won’t work. The end of line resistor need to be in place in one spot only (2 in the network). If it sees more than one resistor it will likely get a CAN network fault and not work.

If the proper ends can be found, it saves splicing into the harness which is much more ideal.

As mentioned though a repeater would be the most ideal solution.

Good luck fellas. Sounds like y’all are in the right track.

L8T, My cable will be over or close to 35 feet. I have to go around the goose neck section by routing to the truck bed approx. 4 feet, to a connector as discussed, then some free slack so it wont rip the connector off the bed about 5 feet(due to trailer swing on the goose neck over the bed making a jack knife turn movement). Run the cable 6 feet back on the gooseneck and 5 feet down the goose neck. Then run at least additional 15 feet towards the rear underside of the trailer. So there is thought on a longer cable. I have 18 GA twisted shield instrument cable to utilize. I would like to use the original TPMS receiver in back of the license plate and add a second receiver under my trailer. The reason as I move the receiver as a single unit to the rear the front tires would loose signals. You say there is a end of line resistor it would create a line fault? Where is the resistor located and could it be removed from what I would call the "new trailer receiver". What does it look like can it be removed? My plan at the moment is to make up a connector that would plug into the existing harness with a short jumper to plug into the existing receiver, Then the harness would continue to the middle section of my trailer closer to my axle sets. a second option is to only run the twisted pair to the trailer receiver and utilize constant power on the TMPS receiver on the trailer as I have multiple 12 volt batteries. I could use a switch so it switches power off until I connect the trailer to the truck? Is this feasible to have a different power source? Is the above feasible running 2 TMPS receivers running at the same time and either the one located at the existing location I can have the end of line resistor removed and installed at the factory location and relocating the original one that was under the license plate relocated to the trailer so it would have the same possible identification for the CAN network?

Thanks

Chuck

Gecko50 · March 2, 2021

On 2/27/2021 at 9:35 AM, Mbower2020 said:

Chuck, I really would like to help you out but I am a little reluctant to give out any of my contact information at this time to someone I only know through a forum. Please don't take any offence to this unfortunately its just the age we live in now. You can buy these connectors on Amazon for less than 15 dollars which I posted previously. Shipping took about half of the time that was stated by Amazon.

I have no problem sharing trials and tribulations throughout the process within the forum. I would rather keep it at that level.

Hope you understand and I thank you for your insight and post as well as the others within the forum which has lead me down this path we are taking.

Mike

Mike, yesterday I did order 2 pairs from Amazon and should be here shortly. Thanks again. I also posed several questions as noted above and see how it comes out. I think with our extended lengths there will need to be 2 receivers one to cover the front tires as well as the rear trailer tires. So IA am hoping this will work?

Chuck

L8T · March 2, 2021

14 minutes ago, Gecko50 said:

L8T, My cable will be over or close to 35 feet. I have to go around the goose neck section by routing to the truck bed approx. 4 feet, to a connector as discussed, then some free slack so it wont rip the connector off the bed about 5 feet(due to trailer swing on the goose neck over the bed making a jack knife turn movement). Run the cable 6 feet back on the gooseneck and 5 feet down the goose neck. Then run at least additional 15 feet towards the rear underside of the trailer. So there is thought on a longer cable. I have 18 GA twisted shield instrument cable to utilize. I would like to use the original TPMS receiver in back of the license plate and add a second receiver under my trailer. The reason as I move the receiver as a single unit to the rear the front tires would loose signals. You say there is a end of line resistor it would create a line fault? Where is the resistor located and could it be removed from what I would call the "new trailer receiver". What does it look like can it be removed? My plan at the moment is to make up a connector that would plug into the existing harness with a short jumper to plug into the existing receiver, Then the harness would continue to the middle section of my trailer closer to my axle sets. a second option is to only run the twisted pair to the trailer receiver and utilize constant power on the TMPS receiver on the trailer as I have multiple 12 volt batteries. I could use a switch so it switches power off until I connect the trailer to the truck? Is this feasible to have a different power source? Is the above feasible running 2 TMPS receivers running at the same time and either the one located at the existing location I can have the end of line resistor removed and installed at the factory location and relocating the original one that was under the license plate relocated to the trailer so it would have the same possible identification for the CAN network?

Thanks

Chuck

I don’t think you can run 2 receivers without reprogramming the module that controls them to understand it’s splitting the signals going to it and you may even have to run two different frequencies due to overlap. You could have for instance the rear truck axle being picked up on both the truck and trailer receivers sending it twice. The way the system is currently designed you can only run one at a time.

I never thought about losing signal from the steer axle if you moved the receiver back. This could definitely pose a problem. Unless reading the trailer is more important than the truck. Ideally, a signal booster or repeater would be the best option to install on your trailer and leave the factory TPMS receiver where it is.

FWIW we have a low bed at work that is 125’ long and it has sensors and brake controls on the rear axle that operate via canbus. The module on the trailer has its own power wire outside of the twisted pair and all the twisted pair does is carry the ground, can-hi and can-low signals. Most can networks are designed to work this way.