It's either on the back side of the turn signal controls or on the dash, depending on the model year.
You open up the steering column and find it in there...
On Kenworth's website: (http://www.kenworth.com/3100_sea.asp), there is a truck locater. Type in your address to find Kenworth trucks and dealerships in your area!
The turn signal flasher relay switch and the emergency flasher relay switch are the same switch. The relay switch might be labeled as the emergency flasher switch, but it is also the signal flasher relay switch.
Hook up a NexIQ box to it.
You can find the flasher relay switch beneath the drivers side dashboard. The flasher relay switch will be above the brake pedal.
You can find up to 250 horse power engines for the kenworth t12000 truck. But, for the best performance you want to go between 180 and 220 horse power engines.
You can find the flasher unit relay switch beneath the drivers side dashboard. The flasher unit relay switch will be above the brake pedal.
If it's an old one with a Grote turn signal switch, you'll find a little sliding gadget under the turn signal handle; pull it away from the steering column and the flashers will go on. (Move the turn signal handle to turn them off.) A new Mack will have a flasher switch with a little triangle icon.
It is right behind the hazard flasher switch on the dashboard, remove the air outlet to the right of it, just pops out with a straight screw driver. The switch /flasher is a solid state device.
The kenworth truck company website (kenworth.com) has a dealer locator option allowing you to choose your state and it will list all the dealer locations including phone numbers and addresses.
The flasher unit is incorporated as part of the hazard flasher switch. Just prise the switch out gently, then release the two red tabs at the rear top and bottom of the switch. Once they are released you can remove the plug and wires.
The flasher is located on the steering column, remove both screws holding the plastic covering. Once it's removed, the turn signal/wipers switch should be visible. The flasher isdead in the center of the switch on the back. Will need to remove the switch to get to the flasher. It's a square flasher and you may be able to find at Oreilly auto parts. That's where i got mine.