Won’t start unless jumped off

ASHARPJEEP

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Jun 5, 2026
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Knoxville TN
Hey guys need some help on what feels tricky.

My 90 with 4.2 won’t start unless it is jumped off by another vehicle. New battery and tests fine, Alternator is fine, just replaced ignition module switch, just replaced key lock switch, just replaced ignition control module.

There is no buzz, clicks, starter clicks etc. silence

I am thinking it May be the control module on the firewall next to the battery sorta under the battery. It has a main supply cable from the batttery and other wires to the 6or so posts. Anyone know what that is called?

Besides that what else can I try to rule out or test? Thanks in advance folks
 
Sounds like a bad battery cable(s) and the extra from jumping it does the trick. You do a voltage drop test at the battery or starter yet? Battery cables can look fine but be in bad shape internally from corrosion.
 
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