FJ40 Checking the Ignition switch
The negative cable to the battery failed yesterday. The round connection that slides over the battery post cracked all the way through. I replaced the cable with a new one, a big strong 1 gauge.
I suspect that my ignition switch has been on its way out but I missed the signs. On the 10th we put installed a new heater core and for that work we disconnected the negative cable. Shortly after hooking everything back up we had a "slow start", you know the kind that sounds like the battery is low. So, I tightened the negative cable connection to the battery post. Yesterday morning we had another "slow start" so I tightned the negative cable connection to the battery post again. Yesterday afternoon, the negative cable connection to the battery cracked.
Upon replacing the cable, the truck would not start. When the key is turned to the start position there is nothing. I checked the fuses and the top 20 amp was broken and I replaced it. All the others fuses check out fine for continuity. With the key in the On position the truck has power to the brake indicator light, the interior dome light and head lights. I did not check any of the other accessories. We put the towbar on and brought the truck home.
At home I pulled the new cable connection at the frame and cleaned the area with sandpaper so that there is a clean connection. Upon hooking it back up, I was successful in getting the truck to start once. Upon the next attempt I am back to nothing when the key is turned to the Start position. While running, everything worked just fine. With the key in the On position, there is power to all the things that should have power. The battery is at 12.7 volts.
So on to my technical questions. How do you test the Start position of the ignition switch? Can I connect a test light lead to the post on the back, ground the test light and turn the switch to Start? If I understand the circuit correctly, if the light turns on then my switch is good and I need to then check for power at the starter.
If my ignition switch tests to be faulty at Start - what is an appropriate way to set up a hot wire so that HutHut can drive the truck while a new switch is on its way?
Ricardo Maestas - Bio Page
1999 LX 470, 1971 FJ-40