Power at PDC, None at Junction Block in-cab? 99xj

1999 xj
4.0 Manual np231

As it stands, I had to have it towed home the other night after no-crank'ing on me at a gas station. Turn key to run, starter clicked once. After smacking it, and key to run again my dash lights came on dim at first quickly coming up to usual brightness, |I turned the key and everything went dead. No dash, dome, radio, ect.

I put a new battery in, tightened my starter bolts (Causing a cruddy ground) and now have no juice in-cab, at keyswitch, dome lights,ect. The pdc has 12v at its main connection point from the battery lead, all fuses in the pdc have checked out as good. As a precaution I have the starter disconnected as it has its own problems I already know about. I have removed the pdc from its mounting bracket and checked physical connections at the pins - 12v.

Im troubled slightly, maybe a circuit breaker gone? I have checked all fuses in the in-cab junction block and they are all good. There are 2 breakers in there, how would I check them?

Moreover, anyone else had this issue? Quick fix? Bueller? Bueller?


thanks in advance

Hoser

Further troubleshooting:

Issue : No visible power in-cab/inst panel/pumps n relays n such when key turned to RUN.


I noticed that I needed a good direct-to-battery ground for my dvom, resulting in voltages at the junc. block. Probably have been there all along.

Second, when I touched the pos. lead against the engine accessory mount for the ac comp, the dvom read 12v. After pulling the bottom two fuses in the pdc (left side of maxi fuses) the reading dropped to 0v. I believe my ign was in Run at the time. After turning it to off, and replacing the fuses, the 12v reading did not occur when contacted against the ac comp mount.

I think something that is on the ign run circuit has come into contact with the body. Out into the cold again I guess haha.

Poor quality wire connections or corroded wires would be the logical starting point.

Clicking and not starting is usually a low voltage issue from:

• leaving the lights on
• a failing battery
• a failing alternator
• dirty, corroded, or loose wire connections
• internally corroded battery wires

Perform routine maintenance of the start and charge systems. Remove, clean, and firmly reconnect all the wires and cables to the battery, starter, and alternator. Look for corroded or damaged cables or connectors and replace as needed. Copper wires should be copper color, not black or green. Do the same for the grounding wires from the starter to engine block, the ground wires at the coil, and the ground wires from the battery and engine to the Jeep's frame/body. You must remove, wire brush, and clean until shiny the cable/wire ends and whatever they bolt to.

Jeeps do not tolerate low voltage, bad connections, or poor grounds.

Place your DVOM (Digital Volt Ohm Multi-Meter) on the 20 volt scale. First check battery voltage by placing your multi-meter's positive lead on the battery's positive post ( the actual post, not the clamp ) and the negative lead on the negative post. You need a minimum of 12 volts to continue testing. Next, leave your meter connected and take a reading while the engine is cranking. Record this voltage reading. Now connect your positive lead to the battery terminal stud on the starter and the negative lead to the starter housing. Again, crank the engine and record the voltage reading. If the voltage reading at the starter is not within 1 volt of battery voltage then you have excessive voltage drop in the starter circuit.

Typical voltage drop maximums:

• starter circuit (including starter solenoid) = 0.60 volt
• battery post to battery terminal end = zero volts
• battery main cable (measured end to end) 0.20 volt
• starter solenoid = 0.20 volt
• battery negative post to alternator metal frame = 0.20 volt
• negative main cable to engine block = 0.20 volt
• negative battery post to starter metal frame = 0.30
• battery positive post to alternator b+stud = 0.5 volt with maximum charging load applied (all accessories turned on)

Test the output at the alternator with your volts/ohms multi-meter. You should be measuring 13.8-14.4 volts. Load testing the alternator is still recommended.

Exchange the ASD relay with the Starter relay in the fuse box under the hood near the battery.

Have your helper turn the ignition key to START while you tap on the starter with a hammer. If the engine starts, you probably need a new starter.

Have the battery, starter, and the alternator Load Tested for proper function in a test machine that applies a simulated work load. Handheld testers are inaccurate and will often pass faulty parts.