Hey all,

I have a '94 5 speed. I had the battery checked at Auto Zone and they assured me the battery was working fine and charged it for me. If it is left for a couple days or is cold in the morning it won't crank enough to start. I can start it with a battery starter kit. I'm assuming something is draining the charge, but I don't have a dome light, glovebox light, or anything on or plugged in. Does anyone know what fuses I can pull to see if it helps at all? Or could it be something else, I'm not thinking of? Thank you for any ideas. I would hate to be jumping this thing before work each day in the North East.

 

Just unhook one battery cable after parking it
After sitting overnight or a few days hook cable back up and see if its starts OK, if not the battery IS NOT "OK", it's self draining, very common in car batteries in cold weather
(just as a heads up, Parts stores employees are not technicians, if they were they would be making a lot more money working somewhere else)

If it starts fine then you do have a unwanted drain in the electric system
You will need an AMP meter, most volt meters have that function
You will hook AMP meter up and THEN, with key off and doors closed, you will pull out fuses in engine fuse box one at a time and watch for Drop in AMP draw

 

Thank you for the reply Ron! You have been a life saver for me. I'll check that out over the next couple of days. I'll try unhooking the battery after work tonight and see how she goes in the morning. If all goes well I'll try checking for AMP drop.

 

Well Ron, I left the battery unhooked last night and it fired right up this morning. If I see the AMPs drop when checking this other method, that will let me know that that fuse is the one draining correct?

 

Fuse 4 in engine fuse box gives EEC(computer) full time power to hold memory, so pull it for test as that's suppose to be a full time drain but only 0.02 amps, 20mA

Also Fuse 2 in engine bay fuse box, OR pull fuse 1 in Cab fuse box, this gives full time power to Radio to hold Clock and presets in memory, 0.01amps, 10mA

If there is still a drain on battery then start pulling other fuses in engine bay fuse box


Below is the power distribution for 1994 Ranger
It is possible, but unlikely, that ignition switch under steering column is not turning off a circuit, if you pull Fuse 1 in engine bay fuse box and amp draw stops then ignition switch should be replaced

 

So I pulled some fuses ans found that fuse 2 in the engine bay was pulling 3.2 amps I believe. I pulled it and started the truck up to find that, as expected, my head unit wasn't working. BUT my headlights stopped working too! If I just rip out the head unit would that solve this?

 

The head unit(radio) may just be miswired, but yes pull it out

Radios often have clocks and electronic pre-sets, so will have a "memory" 12v wire
On the wiring there will be a Key ON 12v IN(so radio only works with key ON), and a Key OFF 12v IN, people often just twist these together, bad idea
Look up the model number to get wiring diagram

Car batteries are usually only 70 to 80amp hours, BRAND NEW
3amp draw is 30amps after 10 hours
Batteries have a hard time starting an engine once below 50%, so 35-40amps
So overnight, 10 hours, it may start, after 24hours NO WAY

 

Thank you again Ron! I'll take the head unit out for now, and look it up. I hope that does it, because it's getting pretty cold up here and I don't want to jump it every morning haha.

Next on my list is to get that heat working for the same reasons! Lol

 

In 1994 the Blend Door for heat in the cab is Cable operated so always works, lol, operate the temp slider and you should hear the Blend door opening and closing, cable is just above glove box opening, has an adjustment, same as cable operated bike brakes

But heater core is prone to clogging up, its the by pass for water pump so always has flow thru it
Cores are cheap and easy to change, 2 hose clamps and 4 screws in the cab

Start engine and let it warm up for 2 or 3 minutes
Feel heater hoses at the firewall, BOTH should be warming up, if just one is much warmer than the other then core is getting clogged up
You can try flushing it, in BOTH directions


You should Reverse the heater hoses at the firewall on ANY vehicle every 2 years or so, this reverses the flow thru the core, so back flushes it while you drive, this can help heater cores last longer

 

UPDATE: I pulled head unit out before we left for vacation. It sat for 11 days in cold weather and started first try when I got home!

I'll be looking into the heat now. Thanks Ron!