my battery light is on when my ignition is off

skullandcrossbones · Oct 17, 2014

I have a 1988 ford ranger with a 2.9 and a 5 speed. When i hook the battery up no matter how i turn the ignition ( even completely off my battery light never goes off) Well i have a feeling i need a new key switch cylinder any way because i dont need a key to turn mine. Could that be the problem? the battery light is on because i believe my alternator is out but either way should it be on even when the "key" is off? also my truck will not crank from the key (it used to without a key by the way) its not the solenoid or starter because i can start the truck by jumping the starter solenoid and it will run (with jumper cables mind you) so i was thinking maybe the new cylinder will fix it? if not do i need an ignition switch? (i believe its on the column close to the plug? i've replaced almost every sensor, i have to buy 2 vacuum lines tomorrow, new distributor cap, wires ,and plugs ( im chasing an idle issue, it seems to idle at 1,000 but runs so rough that it shakes the truck) i can plug up a certain vacuum port and it idles up to 1500 and runs smooth no roughness but way to high of an idle. the vacuum line that was on it broke so i think that may be why and so was the one on the right side of the emissions canister thing at the driver side front of the truck. please help? im more concerned with the battery thing than the idle at the moment though but i gotta wait till payday to get an alternator.

RonD · Oct 18, 2014

Battery light circuit looks like this

Battery----fuse----ignition switch------battery light bulb-------alternator/regulator----"ground"

There should be no power(12volts) at the bulb if ignition switch is in the OFF or ACC setting, only in RUN should there be 12v at the bulb.

The ignition switch is under the steering column, there is a metal bar from there that goes up to the Key switch, when key is turned the metal bar slides the ignition switch contacts into its 4 positions that sends power or cuts power to the various devices.
Yes, it reads like the ignition switch is not being put into the correct position so the 12v to the battery light is not being cut off and the starter relay activation voltage is also not being sent in the START position.

Changing the key cylinder probably won't help, it could be the whole key switch that is worn out or the slider bar or the ignition switch itself, I would start disassembling the steering column to see what is loose or bad.

skullandcrossbones · Oct 19, 2014

how?

How do i replace the ignition switch? I replaced the key cylinder, doesent really help but it needs a key to turn now so i feel safer. but it didn't help haha i don't know much about steering columns so i do not want to go tearing it apart without knowing how to put it back together. everything on this truck is soo clean and original i don't want to go switching columns around in a junk yard if i can fix mine

skullandcrossbones · Oct 21, 2014

umm

So i went through and replaced the ignition switch and the solenoid, now whith jumper cables it will start by the key! Now my only issue is that battery light. when i hook up the jumper cables the battery light still comes on. my fear is when i replace the battery and altenator on the 27th that the light will go off but there is still power to light (my gauge lights don't work so i don't know if there's power to them but the gauges are not on when the keys off? Is it normal for the light to be on even when the key is off if your battery and altenator are bad?

RonD · Oct 22, 2014

The battery light gets 12volts from the ignition switch, so unless it is "on" the light should be off.
This is a Grey/yellow wire from ignition switch to battery light.

On the alternator there is a 3 wire connector, unplug it and see if light is still on.
The Light Green/Red wire on this connector is the "ground" wire for the battery light

skullandcrossbones · Oct 22, 2014

I hooked the battery u with the key off and the light came on, i unplugged the altenator and the light went off. i plugged it back in and my starter solenoid clicked and the light came back on.

RonD · Oct 22, 2014

skullandcrossbones said:
I hooked the battery u with the key off and the light came on, i unplugged the altenator and the light went off. i plugged it back in and my starter solenoid clicked and the light came back on.

Unplug alternator connector and test Light Green/Red wire for 12 volts with key OFF, should be 0 volts.
If it has 12volts the wires are crossed somewhere, battery light is getting 12v all the time.

Starter Relay clicked?
The one on the fender well?

If so there is definitely a wiring issue

skullandcrossbones · Oct 23, 2014

yeah it clicked

Yes it clicked like not turning the truck over. but just clicked. it also does it when i hook the battery up. the trucks wiring does not looked hacked into...what am i missing here? I need to get this thing running right.

skullandcrossbones · Oct 23, 2014

wiring harness

So i spent a bit tracing my altenator wiring harness. and from the 2 plugs on the altenator all the way over to the round plug type connector on my driverside fender there is a total of like 6 splices where its been hacked up and taped back up. since it is a harness that can be unplugged I'm going to go to u pull it monday and grab that harness. then get an altenator and a battery...wish me luck!

RonD · Oct 23, 2014

On an '88 there should be 3 relays on the fender, plus the starter relay.

The EEC relay, has a Brown base, it should click when key is turned on, this powers up the EEC(computer), ignition system(TFI), fuel injectors, and Fuel pump relay(not the pump itself).

The Fuel Pump relay, green base, Computer turns on this relay for 2 seconds when powered up, it won't come on again until engine starts(RPMs above 500), or key is turned off and then on.

WOT(wide open throttle) relay, black base, this is usually only used for A/C cutoff, it shuts off A/C compressor when extra power is needed, i.e. when you press gas pedal to the floor(WOT).

Starter relay, this is also the power distribution for the vehicle.
It will have two large posts.
One post will only have 1 cable on it, it runs to starter motor, only ONE cable on this post, if there are other wires then that will be a problem.
The other post will have the battery's "+" cable and several other smaller wires with it, that's the power distribution post.
These other Wires include alternator and power to fuse boxes and the 3 other relays, all via Fusible Links.

Starter relay will have 1 or 2 smaller posts, the one marked with an "S" should have a wire hooked up, this wire comes from the ignition switch and only has 12volts when key is turned to START, this 12v activates the relay and sends full battery amps to starter motor.
If there is a 2nd small post, it will be labelled with an "I", that was for the Coil "+", it gave coil full battery voltage but only when starter motor was cranking engine, this post is unused or not there in your year.

When you hook battery up, and key is off, there should be no "click" if there is then something is miswired.
When key is turned to RUN(on) the EEC and Fuel Pump relays should click, then fuel pump relay will click again when it shuts off 2 seconds later.

skullandcrossbones · Oct 23, 2014

Here's what's on my starter relay
top post- battery cable going to battery
one yellow wire that's split into 3 different yellow wires
one green wire
s terminal- one small red wire
bottom post- red wire going to starter
ill try to get pictures tomorrow

RonD · Oct 24, 2014

That reads like it is correct.

skullandcrossbones · Oct 24, 2014

does this look right?

does all of this look right? its all on my passenger side near the air box

skullandcrossbones · Oct 24, 2014

the first one shows the starter solenoid the second and third show the one wire into 3 the last shows a plug below the one wire into 3 the looks like it may be missing a wire but i couldnt find it anywhere

skullandcrossbones · Oct 26, 2014

Okay do i found out its not the altenator wiring harness. its what the harness plugs into on the driver side fender. that wiring harness has power with the key off (i used a test light. the plug is a 3 wire ones black/orange, ones yellow and i can't remember the other ine at the moment. its a plug that goes into the fuse panel below the steering column

my battery light is on when my ignition is off

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