PLATE-SIDE BAR 1752214 - Caterpillar

Problem: The actual gear indicator powers up but only the red lamp flashes on the display.
The red lamp flashes very rapidly and the truck gear is never displayed.Step 1.
Replace the actual gear indicator.Problem: The actual gear indicator display lights up with all symbols ON and a "H" showing.
777B Actual Gear Indicator Electrical SchematicStep 1.
Turn the key switch OFF.Disconnect the 4 pin connector from the actual gear indicator.Measure the resistance between the appropriate pins of the 4 pin connector receptacle to vehicle ground (metal without paint). The resistance measured should be as indicated by the following chart for the appropriate vehicle.A low resistance is less than 1 ohm. A high resistance is greater than 5000 ohms. For example; If the vehicle is a 789, 6 speed truck then the following must be true. The 4 pin connector receptacle should show less than 1 ohm of resistance between socket 1 and ground, more than 5000 ohm between socket 2 and ground and less than 1 ohm between pin 3 and ground. Results:A. The resistance measured agrees with the chart (harness good). Replace the actual gear indicator.B. The resistance measured does not agree with the chart. Repair or replace the harness between the 4 pin connector receptacle and ground.Problem: The actual gear indicator display lights up with all symbols ON and a "F" showing.
777B Actual Gear Indicator Electrical SchematicStep 1.
Turn the key switch OFF.Disconnect the 37 pin connector from the transmission control. Disconnect the 7 pin connector from the actual gear indicator. Check the resistance between socket 31 of the 37 pin connector plug and pin 3 of the 7 pin connector receptacle. Check the resistance between socket 32 of the 37 pin connector plug and pin 4 of the 7 pin connector receptacle. Check the resistance between socket 33 of the 37 pin connector plug and socket 5 of the 7 pin connector receptacle. Check the resistance between socket 34 of the 37 pin connector plug and socket 6 of the 7 pin connector receptacle. Check the resistance between socket 35 of the 37 pin connector plug and socket 7 of the 7 pin connector receptacle. The resistance between the two pins in each case should be less than 10 ohms. Results:A. The resistance measured is less than 10 ohms in each case. Go to Step 2.B. The resistance measured is not less than 10 ohms in one or more checks. Repair or replace the harness.Step 2.
Place a jumper wire between socket 34 of the 37 pin connector plug and vehicle ground (metal without paint). Place another jumper wire between socket 35 of the 37 pin connector plug and vehicle