1990 Ranger 2.3 .5 spd .Today drove to work.Cut it off,and about a hour later got in and it started up fine,but died in about 10 seconds.Repeated,did same.Noticed if I held the switch over it would run but gauges would not work,only the tach worked.Now is where it gets weird.The heater was on.Once I turned it off it would crank ,idle and drive,but gauges still not working.So had to drive it 80 miles back home.On the way ran fine,except when ANYTHING electrical was used it would die,theft light would come on,and both turn signal arrows would stay lighted.Even pushing the brakes will kill it.Couldn't run anything on the way home,tried 4 way flashers but they caused it to cut off and on as they blinked.Checked every fuse,etc.I'm stumped.Any ideas on where to look or what it could be...thanks

 

Forgot to add...Got stopped by GSP for no tail lights.While sitting at idle problem cleared up...everything worked fine for about 10 minutes,then it went right back to the weird lights and cutting off if anything was turned on...lights,brake light,etc...

 

Almost sounds like your alternator is failing.

 

It could be a ground issue. Try cleaning the connection to the battery and making sure the nuts are snugged up afterwards

 

Alternator and grounds. Pull every ground wire off, sand down its contact patch, sand down the connector. reconnect tightly. Pull the battery cables off, sand the posts and sand the cables, reattach tightly. Unplug the connector off the alternator, check inside for rust or corrosion. Apply a dielectric grease to the plug before putting it back tightly. Then I want you to get battery voltage across the battery terminals after the truck has sat for 8 hours and report back. Then we need voltages while the truck is idling, when the truck revs up does the voltage go up/down? etc. If you don't have a multimeter go to harbor freight and get one for 4.99

 

+1 ^^^^


Battery/alternator issue and maybe ignition switch..............maybe you never noticed before but all gauges/lights on the dash SHOULD cut off when key is turned to START, this is to give the starter motor all the battery voltage available to turn engine over
If, after startup, when key is turned back from START to RUN(on) the dash gauges don't come back on then ignition switch is most likely problem, it under the steering column, its not near the key

If the ignition switch doesn't turn on all the dash gauges and lights on when in RUN(on) then there would be no alternator charging, Battery Light must be ON with key on engine off, or alternator will never start generating voltage after engine starts
The Battery Light circuit supplies "startup voltage" for the alternator

 

Update....alternator is charging and checks out good at parts store.Replaced the electrical part of the ignition switch with new.Checked all grounds,and added a new one.Pull instrument cluster and checked for bad wires,etc,Took every plug loose and checked and cleaned with contact cleaner.......and the problem still remains...I'm stumped.

 

Parts stores can't check alternators, although they try, lol

Get a volt meter
Test it yourself

 

Ok so today replaced alternator with a new one.Turns out mine was bad...BUT the problem still persist.Same as before turn on headlights...engine dies.You can hear alternator whine from a load as soon as you turn them on.Volt gauge is doesn't move stays over at lowest.Turn on flashers and when they flash the volt gauge jumps even lower as flashers flash.I have removed every fuse,one at time trying to isolate the short and not one makes a difference.All plugs to rear from firewall unplugged doesn't change a thing. No rust in the truck.Cranks and idles fine,no load on alternator as long as nothing is turned on...voltage at battery reads 14.4 idling and 13.4 off...when anything on the truck is turned on headlights/flashers,brake lights etc voltage drops to below 13 ...so I'm guessing a short somewhere...

 

WOW.....feel like an idiot.Found the problem after checking,rechecking and checking again.Guy who owned it before me had put a new horn on.And just happen to have placed the relay over the ground wire on the inner fender on the drivers side so I didnt see that ground.It had lost ground at that point....and after searching thru old post on electrical problems found a post on ground locations and had missed that one.......problem fixed...

 

Good work

 

This is why i said the FIRST thing you do is check grounds. its free and its easy. You won't make that mistake ever again I bet

 

Nope,what thru me off was I saw the ground strap on the rear,and the one on front.And the signs it was doing did not act like a ground.It was almost like it was back feeding power into other circuits.And since the truck is new to me had no idea what had been done to it.Because usually when problems like that it's always the last thing done to it.And had I known he had replaced the horn with a aftermarket air horn that would have been my first place to look.Instead it was last after I had went full tweaker and tore the whole thing apart...lol But I did fix alot of things in the process.Speedo didnt work,does now.Dash lights didnt,wire had pulled loose of the plug to instrument panel,fixed that.So I should be good to go.Last ranger I had sold it with 300k on it.Not sure on this one on mileage,runs good,get ALOT better gas mileage than my excursion.I've got a 1985 S10 we are building with a sb400/th350 just finishing up the mechanics of it next week.So I bought this one as my work truck.I drive between 100 and 250 miles a day 6 days a week.