No start issue - no ground on starter relay terminal 85 in PDC

Tonye48

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Looking for some insight on a no start issue on my 2001 TJ 4.0 5spd. The starter isn’t getting power to the solenoid when the key is turned. When relay terminal 87 is jumped to 30 it will power the starter and crank the engine. When the ignition switch is turned to the “on” position I am not getting a ground reading on terminal 85 for the starter relay. I believe you this is my issue. The problem is that I cannot track down the cause of the bad ground to the starter relay.
 
There is a downloadable PDF for the Factory Service Manual for your year TJ.
Section 8W-21-2 contains a schematic for the Starting Circuit.
On the Starter Motor Relay terminal B5 (yellow/red) is from the Clutch Pedal Switch, terminal B3 (brown/light blue) is the ground, terminal B1 (pink/black) is from the PDC and terminal B2 (Brown) goes to the starter solenoid.
I would jumper the Clutch Pedal Switch wires (yellow and yellow/red) first to see if that solves your problem.

https://wranglertjforum.com/attachments/2000-2001-tj-service-manual-pdf.14036/
 
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Looking for some insight on a no start issue on my 2001 TJ 4.0 5spd. The starter isn’t getting power to the solenoid when the key is turned. When relay terminal 87 is jumped to 30 it will power the starter and crank the engine. When the ignition switch is turned to the “on” position I am not getting a ground reading on terminal 85 for the starter relay. I believe you this is my issue. The problem is that I cannot track down the cause of the bad ground to the starter relay.
It will only send a ground to the starter relay to energize it when it's in the Start position, not when it's in the On position. Your problem could be a bad ignition switch but it's more likely to be a broken ignition switch actuator pin which is a separate assembly from the ignition switch that sits behind the ignition switch. They do break often enough that I bought a spare to carry with me. This is what I bought... https://www.amazon.com/gp/product/B004BYX8W8/?tag=wranglerorg-20
 
The PCM will only send a ground to the starter relay to energize it when it's in the Start position, not when it's in the On position. Your problem could be a bad ignition switch but it's more likely to be a broken ignition switch actuator pin which is a separate assembly from the ignition switch that sits behind the ignition switch. They do break often enough that I bought a spare to carry with me. This is what I bought... https://www.amazon.com/gp/product/B004BYX8W8/?tag=wranglerorg-20


It will only send a ground to the starter relay to energize it when it's in the Start position, not when it's in the On position. Your problem could be a bad ignition switch but it's more likely to be a broken ignition switch actuator pin which is a separate assembly from the ignition switch that sits behind the ignition switch. They do break often enough that I bought a spare to carry with me. This is what I bought... https://www.amazon.com/gp/product/B004BYX8W8/?tag=wranglerorg-
It will only send a ground to the starter relay to energize it when it's in the Start position, not when it's in the On position. Your problem could be a bad ignition switch but it's more likely to be a broken ignition switch actuator pin which is a separate assembly from the ignition switch that sits behind the ignition switch. They do break often enough that I bought a spare to carry with me. This is what I bought... https://www.amazon.com/gp/product/B004BYX8W8/?tag=wranglerorg-20

I have pulled the ignition switch and actuator pin and the actuator pin is not broken. I removed the ignition switch and checked for power on the red starter wire on the harness plug and measured 12.7v, then put a jumper wire from the red starter wire to the yellow wire directly below it on the ignition switch harness plug to bypass the ignition switch and remain in the “start” position. Still no ground signal. I also bypassed the clutch safety switch by putting a fuse in fuse slot 20.
 
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This will help, it's for your 2001.
Capture2.JPG
 
Tonye48 said:
I have pulled the ignition switch and actuator pin and the actuator pin is not broken. I removed the ignition switch and checked for power on the red starter wire on the harness plug and measured 12.7v, then put a jumper wire from the red starter wire to the yellow wire directly below it on the ignition switch harness plug to bypass the ignition switch and remain in the “start” position. Still no ground signal. I also bypassed the clutch safety switch by putting a fuse in fuse slot 20.

Since there is no GROUND signal to pull in the Starter Motor Relay then it is time you trace the Brown Lt Blue wire thru C104 to the Black wire in C154 to the grounding terminal at G105. You need to find where there is either a loose ground or oxidized terminal in C104 or C154.
 
Thank you for all of the replies, after re-checking it everything today using the diagrams y’all have provided I realize I was confusing terminal 86 with terminal 85. I verified that I have a good ground on terminal 85. I do not have 12 V on terminal 86. These are all of the readings I have taken.

85 to ground “ohms” = good ground

terminal 30 to ground = 12.5v

30 to 87 = 12.5v

86 to ground = 0v

85 to 86 = 12.5v

85 to ground “dc volts” = 12.5 v

87 to ground = 0v

All measurements were taken with a jumper wire bypassing the ignition switch in “start” position
 
Inspect the Ignition switch harness for signs of overheating and ensure there is 12V coming from terminal 10 of the Ignition Switch harness when the switch is placed in the Start position.
Find Connector 106 and inspect the wiring harness and connector terminal 9 for oxidation.
Test the Clutch Pedal Position switch for continuity when the clutch is depressed OR jumper the switch.
 
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