So I got new tires in the 285-75-16 and the shop put 35 PSI in the tires. Well every time I get on the highway my TPMS light come's on, but goes off when I'm on back roads. So my question is what PSI should I run in a M/T in 285 size.
Thanks in advance!

 

Wow! I thought that someone would have a solution by now. I did the same thing and have the same problem. Even ran the tires at the recommended 30 psi instead of 35.

 

There's a lot of solutions. This topic has been discussed many times here. Just do a search.

 

Read them all, now tell me one that works.

Reprogrammed the sensors, numerous times. Took it back to tire rack, they reprogrammed twice and checked for codes, raised pressure, lowered pressure.

So tell us what the actual problem could be, or a hint.

 

Okay, still no answers? Took it to the dealer, all sensors check okay, code check, none, tire pressure at 30 per dealer. Was told that the controller for the TPMS is the same as the remotes, remote control working.
Anyone else have a suggestion?

 

I run my 285's at more like 38 psi and usually only get the TPMS warning when it is really cold outside. Also get slightly better gas mileage at that pressure albeit with a slightly firmer ride. Otherwise if you are getting TPMS warnings and you know your pressure is OK - ignore them.

 

TPMS light on after new tires mounted? That's an easy 1... The "general service tire and lube guy", cracked a sensor when mounting the tire. The mounting shoe should never ever come close to the sensor when mounting a tire. I've seen this happen numerous times, and I always end up giving the customer a free sensor.
Take it back to the shop, have them dismount the tires and look at the sensors. It's only a piece of plastic with a metal stem.

 

Starting to make sense, the service TPMS come on around first start, then after about 15 minutes of driving, if I turn the truck off and then back on, no TPMS fail. No codes are being thrown and only started after I had the tires change. All sensors read okay when checked by the diagnostic machine and code right up. I have a hunch that it's the left rear, since I had trouble manually programming it. Although the dealer and tire racks machines indicate its transmitting properly.

 

those flimsy wires near each wheel I think those are the pickup devices for each sender. they can be damaged

 

I get random SERV TPMS errors. Sometimes it is on for 5-10 minutes and then goes off. I did the relearn 3 times and no making it go away. I rund about 36 psi. I did get the low tire pressure warning on super cold days. I just ignore the warnings.