Novak Conversions Jeep Wrangler YJ radiator

YJ No Crank, possible voltage drain?

nathanmhli

New Member
Joined
Aug 16, 2025
Messages
1
Location
Ithaca, NY
Hello all,

I drive a 1990 YJ with the 4.2 and 5 speed. Recently, the car has not even been cranking, yet the day before would start up and drive just fine. The dash still receives power, all of the gauges light up, the dome lights still work when I open the car door, and the headlights work. The voltmeter reads around ~10v at this stage. When the car ran, it had a perfectly smooth idle, and the battery displayed 14V as normal. I recently purchased a new battery (old battery was old, so needed a new one anyway), tightened the connector to the terminals of the battery, cleaned the starter relay, cleaned the ignition switch, and know that the starter relay is good since I tested it with the working horn relay.

I was able to start it with a portable jump pack. Should I treat this as a voltage drain or power draw issue? Or could it be something like the battery cable? If so, where to start diagnostics? Would greatly appreciate any input. Thanks.
 
10v is a low voltage for a battery, especially a newer one. See if you can get it charged up, and then get an amp meter on it and see if you have a draw with the car off. It sounds like your alternator is charging, as you had 14v with the car running, but might as well get it tested at a parts store for free just to be on the safe side.
 
Novak Conversions Jeep Wrangler YJ radiator