2021 Aisin Tow Haul Doesn't Engage

[The1adman]

I have a 2021 3500 SRW HO/Aisin. About 25% of the time if I don't engage Tow/Haul prior to putting the truck in drive it won't engage. Ex. if I start driving and push Tow/Haul the light comes on the instrument panel like normal. but wont actually engage no matter how many times the cycle the button, even if I stop put the truck in Park and engage before shifting into Drive.

When this happens the only way to engage Tow/Haul is to shut the truck off, restart and then when I press the button it will engage. Like I said this happens about 25% of the time. My 2017 never did this and I had 4 times as many miles as my 21. Anybody else have this issue?

 

[Brewbud]

Strange. I never engage Tow/Haul until after I am in Drive and I haven't had a problem. Although, unlike in my 2007, I don't use it much.

 

[The1adman]

Strange. I never engage Tow/Haul until after I am in Drive and I haven't had a problem. Although, unlike in my 2007, I don't use it much.

Yeah thats how I have usually done it in the past until this truck because it wont engage. The problem is I sometime forget until I'm already driving. Seems odd every indicator says Tow/Haul but it doesn't actually engage. Guess its not a common problem since no one else has commented to have experienced it.

 

[RV_Goose]

Seems like odd behavior. My 2020 3500 dually HO Aisin doesn't do that.

 

[Nd79]

How do you know it is not engaged if both the button light and the dash light are on? Just by drivability?

 

[Diesel42]

Thanks for the info. I could have sworn last week while pulling my trailer/backhoe the tow/haul wasn't working(21 Cummins H.O. 3500). The light came on the dash, however I could tell by the mannerism of the trans/engine/ and braking wasn't acting correctly. Was questioning myself as crazy but your post confirms what I was noticing. I'm going to have to keep my eye on this. Please keep us posted on yours.

 

[The1adman]

How do you know it is not engaged if both the button light and the dash light are on? Just by drivability?

Yes the trans doesn't downshift with exhaust brake on, will up shift into 6th and lug engine. Very noticeable difference when towing 15K lbs. The bummer is trying to find a place to pull over, idle the truck, shut it off, restart, and then select Tow/Haul and its fine.

 

[The1adman]

Thanks for the info. I could have sworn last week while pulling my trailer/backhoe the tow/haul wasn't working(21 Cummins H.O. 3500). The light came on the dash, however I could tell by the mannerism of the trans/engine/ and braking wasn't acting correctly. Was questioning myself as crazy but your post confirms what I was noticing. I'm going to have to keep my eye on this. Please keep us posted on yours.

I guess its not common from my experience with my 2017 and the reply's. I won't let the dealer touch it, even if they could repeat and fix it, the truck would have 6 new problems I would have to deal with. I guess Ill live with it.

 

[Brutal_HO]

I can switch mine in and out of TH at will at any point.

Same goes for Exhaust Brake FULL ON/AUTO/OFF.

What you are experiencing is not normal.

If the dealer won't address it, escalate with @RamCares

 

[The1adman]

I can switch mine in and out of TH at will at any point.

Same goes for Exhaust Brake FULL ON/AUTO/OFF.

What you are experiencing is not normal.

If the dealer won't address it, escalate with @RamCares

I agree its not normal. My 2017 was the same as yours. The exhaust brake switches Full/On/Off anytime, never been a issue. The Tow/Haul will as well, its the 25% of the time the truck doesn't recognize it.

 

[Southernspeed]

That would seriously piss me off. Tow/haul, especially when combined with the exhaust brake, is a MAJOR driver aid when hauling heavy. I totally hear what you're saying about the dealership, really, but the inconvenience you're experiencing surely must outway the 'dealer affect'! Plus it's more than likely an electrical/sensor issue which may effect other functions eventually unless the tow/haul is a stand alone circuit/system?

 

[The1adman]

That would seriously piss me off. Tow/haul, especially when combined with the exhaust brake, is a MAJOR driver aid when hauling heavy. I totally hear what you're saying about the dealership, really, but the inconvenience you're experiencing surely must outway the 'dealer affect'! Plus it's more than likely an electrical/sensor issue which may effect other functions eventually unless the tow/haul is a stand alone circuit/system?

Thanks Southernspeed. Yes, with 15k lbs on 7-8% grades it is a major driving aid, its night and day difference controlling the truck/trailer down hill. Unfortunately the only two dealers near me are that bad. My next closest dealer is 130 miles 2.5 hour drive. I would expect the "cant duplicate" response.

 

[Brewbud]

Is there a fuse on the circuit? I would double check to make sure all your fuses are plugged in. It's a longshot, but many little intermittent quirks have been attributed to the fuses not being fully inserted.

 

[The1adman]

Is there a fuse on the circuit? I would double check to make sure all your fuses are plugged in. It's a longshot, but many little intermittent quirks have been attributed to the fuses not being fully inserted.

Thanks Brewbud. I don't know if there is a fuse for that circuit but I saw in other posts about fuses not being fully seated and did that first thing when I got the truck in February. As others had mentioned most of mine were not seated.