electrical shutdown

Having a recurring problem with what seems to be either relays or possibly ignition switch. Replaced control module which seemed to fix problem for about a day...then it came back. Losing power to interior, kills juice to dash gauges, clock, etc. It will then reset and away I go...for a while then on the side of the road I sit again. Starter will crank, but no fire until whatever it is resets. Trying to avoid the nightmare of having to meter circuits and spend hours, if not days tracing wires.

Perplexed...know this vehicle all too well. this one is a head-scratcher. from the day i purchased it, it has fought me on every thing...every inch. almost like rejecting a new heart! also have a query posted on the front crap-shaft. tomorrow its getting a new coil and ignition switch...it'll b***h, i'm sure! Any ideas?

85cherokee said:

Having a recurring problem with what seems to be either relays or possibly ignition switch. Replaced control module which seemed to fix problem for about a day...then it came back. Losing power to interior, kills juice to dash gauges, clock, etc. It will then reset and away I go...for a while then on the side of the road I sit again. Starter will crank, but no fire until whatever it is resets. Trying to avoid the nightmare of having to meter circuits and spend hours, if not days tracing wires.

Perplexed...know this vehicle all too well. this one is a head-scratcher. from the day i purchased it, it has fought me on every thing...every inch. almost like rejecting a new heart! also have a query posted on the front crap-shaft. tomorrow its getting a new coil and ignition switch...it'll b***h, i'm sure! Any ideas?

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So the engine stalls when the interior lights go out? Or do the lights go out while the engine still runs?
I once had my Ignition switch melt on me the lights, radio, wipers... would all cut out, if I jiggled the key I could get them back on. No issue with starting the engine. check out that switch issue.
Ignition switch thread


Engine turns, but wont start?
Thats probibly a spark issue, check your fuel pressure, check your spark.
Check the coil first, secondary and priamary resistance (easy to test)
you have a new ECM..

No spark on mine was once the CPS sensor.
CPS (Crankshaft Position Sensor)
$47ish autozone, can prevent spark at coil, sputtering, stalling while hot, and prevent starting. Disconnect and check the CPS resistance. Should measure about 275 ohms resistance. Re-connect and Should generate about 2.5vac when motor is cranking. The CPS is Located at the 10 O'Clock position on the drivers side top of the transmission housing, held by two 1/2in bolts and feeds up to a 3 pin connector with only two wires going to the connector. Try unplugging and re-plugging the connection a few times. If that seems to help, bypass the connection permanently by soldering the wires, use shrink wrap to insulate the exposed soldered connections.

no fun.

Driving down the road or sitting at a light, the thing will just die...dash gauges, clock, radio all shut off. Without touching anything, all will come back after about 40 seconds, it will restart and off I go. Had the opportunity the other day (while sitting) to stare under the hood while this happened...constantly! On..off..on..off, bizarre! Relays kicking on and off, radio blaring, then silent, etc. Like having freekin' ghosts! Just replaced the alternator today and haven't had a chance to drive it yet...friend with auto electrical experience tends to think it might have been built-in voltage regulator taking a crap. Makes sense I guess. Only happening in the heat of the afternoon, it seems. Will know more tomorrow.

The connector for the accesories (radio, rear wiper, heater) is the 3 wire one on the ign sw (top of column - under dash)- I have seen the connector melt on the brown wire - giving a complete - or partial failure. You might check that - good light to check ign sw and connector.

There is a TSB on the C101 connector. It is the big one above the brake master cylinder. It gets intermittent quite often. The TSB actually says to cut out the connector and simply splice the harnesses together. It is a common problem. For the moment, try unplugging the connector and replugging it. When I did my engine swap I just got rid of it.

85cherokee said:

Driving down the road or sitting at a light, the thing will just die...dash gauges, clock, radio all shut off. Without touching anything, all will come back after about 40 seconds, it will restart and off I go. Had the opportunity the other day (while sitting) to stare under the hood while this happened...constantly! On..off..on..off, bizarre! Relays kicking on and off, radio blaring, then silent, etc. Like having freekin' ghosts! Just replaced the alternator today and haven't had a chance to drive it yet...friend with auto electrical experience tends to think it might have been built-in voltage regulator taking a crap. Makes sense I guess. Only happening in the heat of the afternoon, it seems. Will know more tomorrow.

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Did you really clean your battry terminals? wire brush them good.

The Ignition switch could still be your issue.

The wiring harness is a good idea too.

I doubt the alternator could be the issue. The truck could run with the alt completely removed, just your battery would drain over afew trips...if you battery was actually too low for it to kill the deck and lights it would be too dead to start back up. it would down to liek 10volts for the deck to cut out...

A bad power wire, or bad ground to the engine can cause it to die like this, and the battery would be good, so it could restart. clean up all the grouds you can find to your battery.

have fun.