LS 170 Electrical Problems

Hello all,
My LS 170 was running fine the other day and suddenly died as if the key was turned off. The EIC panel began to flash on and off erratically only once in a while staying on long enough to get through the self test and back to the glow plug count/ engine start point. I checked the seat switches and they seem OK. I checked the key/start switch and it did have a loose connection but cleaning and tightening didn't fix the problem. I also pulled the EIC panel down and cleaned the connectors. I have power to the panel but don't have a schematic to know which lead is supposed to have voltage from the seat switch etc. Could a bad panel be intermittent like that? Can anyone help point me in the right direction?

What I'm seeing:
Seat switches work but even if they failed it wouldn't shut down a running machine it would just lock the hydraulics.
Machine will start and run with run/service switch in the service position. (but no hydraulics as expected)
Sometimes the EIC will stay on long enough to get to the start engine point, engine will start, hydraulics will work but after a couple seconds the engine will act like the key is being turned off and on (fuel solenoid) and will die.
Sometimes if I smack the EIC it will power on and may or may not get all the way through the self test.

Thanks,
Orchard Ex

You have checked the engine side fuses and the ones in cab I'm assuming?

The EIC boards do go bad, but its best to rule out wiring and such first.

Red/lt green wire goes to pin 14 in connector p2 for constant battery power to EIC

Black wire in pin 13 connector p2 is ground

Power from seat switch goes to EIC at pin 4 of p2 only when service/run is in run position

Power from seat belt goes to EIC at Pin 11 P2 through light green wire when buckled

Key on power goes to pin 12 p2 EIC through orange wire

Key on engine off power travels from acc side of switch to pin 11 P1 through lt green/black wire.

Trace all of that and if you can run voltage drop tests on the wires that may also help you find an intermittent short.

Thanks. I know that I have the constant power to the end pin on one of the connectors but that was all I could tell before. This will help me wring it out.

durallymax said:

You have checked the engine side fuses and the ones in cab I'm assuming?

The EIC boards do go bad, but its best to rule out wiring and such first.

Red/lt green wire goes to pin 14 in connector p2 for constant battery power to EIC

Black wire in pin 13 connector p2 is ground

Power from seat switch goes to EIC at pin 4 of p2 only when service/run is in run position

Power from seat belt goes to EIC at Pin 11 P2 through light green wire when buckled

Key on power goes to pin 12 p2 EIC through orange wire

Key on engine off power travels from acc side of switch to pin 11 P1 through lt green/black wire.

Trace all of that and if you can run voltage drop tests on the wires that may also help you find an intermittent short.

Click to expand...

All the fuses are good, all of the pins /conditions above check out good.
Just in case anyone is referencing this thread later - The seat belt harness and pin 11 on p2 only get power if the seat switch is closed while the seat belt is buckled. I had the seat switches out and that one took me a minute to realize that the belt was chained with the seat switch power.
At this point the panel stays dark and the alarm sounds with the key on no matter which position the Run/Service switch is in also.
Not looking good...

Turned out to be a bad EIC. Ordered a reman'ed unit and it fired right up like new.

Yes the power comes from a 5amp fuse in engine panel to the seat switch/switches. The seat switch must close to send power to the seat belt switch. Only only of the switches needs to close if you have two seat switches. Then the power goes to seat belt switch and once that is closed it travels to the EIC.

Glad you got it going, EIC boards go bad often but there's a lot to check before having to replace one.