# 1994 hb 2wd manual Does it need 2 inhibitor relays



## nissanhb3227 (Nov 28, 2013)

I found out that I had bypassed the inhibitor relay using the grey plug by the battery. I replaced one of the blue relays but she still wont start without the bypass.


Nissan Nut


See pic above - Nissan Nut

Update --Tested all relays with voltage and ohms and all passed. Truck still wont start without the bypass jumper


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## smj999smj (Jan 1, 2006)

I'm assuming you jumped the switch side of the interlock relay harness, so that means the switch side harness circuit is okay. Since you already replaced the relay, we'll assume for the meantime that the relay is not the problem. This would mean the problem is on the circuit for the solenoid side of the interlock relay. This is the gray plug on the interlock relay with the smaller terminals. When the key is turned to "START," both gray plugs on the interlock relay are powered on the black/yellow wires to those plugs, which share a common power source from the ignition switch. Since jumping the switch side connector allowed the vehicle to start, that would indicate power on that circuit. Use a 12v test light to confirm power at the black/yellow wire on the solenoid side harness plug for the interlock relay (with the ignition switch in the "START" position). If there is no power, there is an open between the terminal and the common splice for the two black/yellow wires.
Once you have confirmed power at the black/yellow wire at the solenoid side harness connector of the interlock relay, we can then test the circuit between the interlock relay and the clutch interlock switch on the clutch pedal, which should be a light green wire. When the ignition switch is turned to "START," there should be power at the light green wire at the harness connector for the clutch interlock switch at the clutch pedal. If there is no power (and assuming the relay is good), then you will need to check for an open or short circuit within the light green wire between the clutch interlock switch and the interlock relay. If there is power at the clutch interlock switch, then we move on to testing ground circuit of the clutch interlock switch.
The black wire at the clutch interlock switch (at the clutch pedal) runs through "Joint Connector C" and then to two body grounds. The simple way to test the circuit is to jump the clutch interlock switch and try to start the vehicle (make sure the trans is in neutral or the clutch is depressed so you don't start it in gear). If it starts, then you know the ground circuit is good and you will need to replace or adjust the clutch interlock switch, as needed. Another way to check it would be to use a continuity tester or an ohmmeter to confirm continuity to ground on the ground circuit, or connect a 12v test light to a power source to test for ground at the circuit. If there is no continuity to ground, then you will need to trace the black wire circuit from the clutch interlock switch to Joint Connector C to the two chassis ground points and repair the circuit, or replace the joint connector, as needed. 

This all said, I would start at the clutch interlock switch. Since replacing the relay didn't fix the problem, the next likely place is the interlock switch. Remove the jumper from the relay and install the relay. At this point it will not start by your description. Jump the clutch interlock switch at the clutch pedal and see if it starts. If it does, then you know the switch is the problem. If it doesn't start, then proceed with the circuit checks as described above.


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