TC48DA Safety Controller

[lfc]

My brother was harrowing with his TC48Da, and heard a loud pop under the hood/dash. He set the brake, got off to look, and a few seconds later he saw smoke coming out from around the steering wheel. The engine died before he could shut it down. Smoke went away, but the tractor wouldn't start then. He removed the side panel and saw that the safety controller had an oily wet spot on it, and what appears to be a small crack on the bottom. All other wiring looked fine. Dealer has a new controller is stock (been there since 2008 they said) so this can't be a common problem, but has anyone else heard of this happening? He's on his way now to get the new part and give it a try.

 

[jinman]

The next loud noise you'll hear is him hitting the floor when they tell him the price of an operator safety module. I think there are several that vary in price from $200 to $250. I hope his is one of the cheaper ones. I've only heard of one other person on TBN with one that went bad. It wasn't on a TC48 or TC55.

 

[pacerron]

I would think he would want to do some serious trouble shooting before popping in a new one and possibly see it go up in smoke
at a cost of $200-250.

 

[lfc]

Thanks everyone for the help. I never remember reading about chronic issues with them, and a quick internet search revealed nothing. He did check the wiring to all of the safety switchs, and found no issues. Plugged the new one in, and it started right up. It was $250, but that is about the only reapir he has made to it so far, so you can't complain about that. He said the hardest part was getting the screws lined up when he put the lower dash cover back on.

 

[mweir2]

Thanks everyone for the help. I never remember reading about chronic issues with them, and a quick internet search revealed nothing. He did check the wiring to all of the safety switchs, and found no issues. Plugged the new one in, and it started right up. It was $250, but that is about the only reapir he has made to it so far, so you can't complain about that. He said the hardest part was getting the screws lined up when he put the lower dash cover back on.

I found this, plus some other discussions/complaints. Had the same problem with mine (price is now $350 in 2018). I thought my findings reported below, where I disclose how to temporarily jumper the safety connections, might be helpful to new readers. This should be applicable to the TC55, and maybe others, but you should carefully study your own schematic. Parts departments may print out a copy for you.

CAUTION: WITH THIS CONNECTION, NONE OF THE SAFETY INTERLOCKS ARE PRESENT. YOU CAN BE HURT OR KILLED. THAT'S NOT MY RESPONSIBILITY!

I have a late-series TC48DA (s/n after HV11282). Earlier this year it suddenly failed to start. The following remarks describe connections to the safety module, which I found faulty, and how to provide temporary functionality with three jumpers. A new module fixed the problem.

Diligent study of the schematic allows the module's connections to be discovered, and functions to be inferred. These names are mine.

pin function signal
1 not connected
2 start relay coil (12V to operate)
3 glowplug relay coil (12V to operate)
4 safety alarm (12V to operate)
5 fuel solenoid (12V to run)
6 glowplug request (12V when key in preheat position)
7 accessory power (12V when key on)
8 seat switch (12V when operator seated)
9 parking brake switch (12V when set)
10 12V unswitched
11 ground at cyl. head
12 not connected
13 not connected
14 parking brake light (ground to illuminate)
15 glowplug light (ground to illuminate)
16 PTO light (ground to illuminate)
17 start request (12V when key in start position)
18 accessory power (12V when key on)
19 shuttle switch (12V in neutral)
20 PTO switch (12V when off)

After dismounting the module and disconnecting its connector, voltage measurements and judicious jumpering disclosed or confirmed the signals. Since the glow and start requests are the same polarity as the associated coil, jumpers can be used to temporarily enable function. Three jumpers:
18 to 5
6 to 3
17 to 2
allow full operation. No safety interlocks are active, and the associated dash lights do not function. If you use the preheat (glowplug) function, be sure not to hold the key in that position for more than about 4 seconds, just as the module would do.

I used insulated 22 gauge solid wire (about .024 inch conductor diameter) about 3 inches long, stripped 1/2 inch at each end. Smaller or larger gauge might be used, but too large wire might spread the contact fingers so much that they would not make good contact with the module's connector when reinstalled.

Looking at the face of the harness connector, pin numbers are
|------------------------------------------------|
| 20 19 18 17 16 15 14 13 12 11 10 |
| 9 8 7 6 5 4 3 2 1 |
\-----------------------------------------------/
The chamfered corners, and the big gap in one row, help keep you oriented.

CAUTION: WITH THIS CONNECTION, NONE OF THE SAFETY INTERLOCKS ARE PRESENT. YOU CAN BE HURT OR KILLED. THAT'S NOT MY RESPONSIBILITY!

Mike (sorry the formatting seems to be lost at the forum. The main loss is the absence of a gap in the lower connector row, between 6 and 5, below 16 and 15)