Amp drain from radio, radiator tip, 1998

[KentAshton]

These forums have been very useful to me so I want to pass along a tip about finding amp drain that was running down my battery. It was the radio drawing .5A (500ma). Apparently this not the usual problem but others have mentioned it. I read that the usual amp drain after the truck has sat 30-45 mins and the GEM has turned off the Battery Saver Relay should be about .030-.070A (30-70 ma) depending on your truck. Mine was a plain vanilla 1998 Ranger with no keyless entry. The first problem was finding the battery saver relay which on this truck is behind the passenger airbag and accessed by dropping the glove box and removing 3 airbag bolts. On other trucks it may be above the gas pedal. Along the way, I unnecessarily replaced the GEM, the battery saver relay, the ignition switch and finally removed the B.S.R. The radio draw seemed to be intermittent because it did not show up initially when I pulled fuses one-by-one. Finally, I saw a .5A drain every time the radio connector was plugged in even with the radio and ignition off.

As others have said, it is tricky to find an amp drain because every time a door is opened, or the key is switched on or the battery is reconnected, the GEM restarts the timer circuit, keeping the B.S.R. on and powering dome lights. I bought a battery knife switch on ebay which let me disconnect the battery easily during the month(!) I was troubleshooting this problem. It also allowed me to let the GEM time out, hook up my amp meter to the knife switch posts and open the knife switch to measure amp drain without breaking the battery circuit and resetting the GEM. Don't forget you are measuring amps and change your VOM wires accordingly and, oh, yeah, if you go back to measure battery voltage, switch them back! [New VOM fuses are on order. ] Also, if you are an electrical newbie, don't confuse AMPs with Milliamps (1A = 1000ma).

My original radio was a cassette model, P.N. F87F-19B132-AB. I got a junk yard radio with a CD player that seems to have solved my problem. All the junkyard trucks of the same vintage had the same connector even with some differences in the faceplate. A site called https://www.the12volt.com/ was helpful. I opened up the bad radio but could not see any obvious reason why it would drain .5A.

Another tip: It has been a good truck although last week the radiator split on a plastic side. I replaced the radiator and it was a good time to replace the fan clutch and water pump. Not a small job but doable. The new radiator had two brass outlets for transmission cooler lines--I don't have a transmission cooler. I fiddled for half a day trying to find plugs for the outlets then a nice radiator man told me "You don't need plugs. The transmission coolant just circulates in a small chamber between the brass outlets which are not connected to radiator coolant."

Hope this helps someone trying to wrench on his 25 year-old ranger.

 

[franklin2]

Don't forget you are measuring amps and change your VOM wires accordingly and, oh, yeah, if you go back to measure battery voltage, switch them back! [New VOM fuses are on order.

Years ago I was working in a manufacturing plant, and I had been doing some amperage testing also with my VOM. I did forget to re-configure the meter, and when I went to test a 480vac motor circuit, my meter leads each ended up being a 1 inch shorter than they were originally. Fuse wasn't quit fast enough, even though it did blow.