2nd Gen Non-Engine/Transmission Need help troubleshooting Dad's truck-Electrical

[KBennett]

EBottema is really gonna like this... :-laf

My Dad is having electrical problems with his truck(see sig). When he lets it sit for a couple days the batteries seem to drain most of the way. He only gets a few cranks and then it quits. He took the batteries to the auto parts store and they said that they were pretty good and to look at the alternator.

If he plugs the block heater in it seems to start right up.

Could the batteries be bad and with the block heater on, the grid heaters are not turning on, drawing the batteries down?

I am thinking bad batteries. What do you guys think?

What turns the grid heaters on on the 12V 2G trucks and at what temp?

 

[zstroken]

Problems

If the auto parts store says batteries are ok I would tend th think they are ok. shut the truck off and put an amprobe on it. It may take about 20-30 seconds but the batteries current should be nearly zero(<less than . 1 amps) You might also put a voltmeter on them after they sit for a few days and take a reading. could be starter or electrical connections too.

 

[CarlJensen]

Did the parts store load test the batteries? They can read good voltage but a load test is the only way to tell. Sounds like a drain on them all the time(amprobe should tell you as zstroken said). Shorted line? May have an alternator that is not charging them back up for you. Grid heaters run when manifold temp. gets below 5o degrees on mine, but they vary by year, can't remember what yours is. Turned on by temp sensor via the computer.

 

[HoleshotHolset]

Since your Dad's truck is a '98 12-valve... the grid heaters will come on just about all the time. They're controlled by the ECM which is hell bent on cycling them until you drive down the road and hit 26(?) MPH.



My '94 is MUCH more intelligent when it comes to the grid heaters... when ambients are above a certain temperature (?) they don't come on at all.



Sorry I can't be much help with the constant drain... My '98 had a screwy switch for the glove box illumination. The only reason I found it was that it would flash while driving down the road at night. I wonder if his glove box light switch is goofy...



Matt

 

[tp0d]

Have you done anything with the starter contacts at all? Bad contacts will require more voltage to crank over. and a cold truck has more internal resistance to movement than a warm truck does.



I`ve seen some of the stock radios go screwy and pull more power than they should from the 12v constant lead (orange). this could be an issue. doing the amp probe as suggested above is a very good idea. You can do a probe check with a meter capable of at least 10amps. . Go into the main fuse box next to the drivers battery, and disconnect the right red lead. This is the battery feed into the fuse box. Hook up your meter between those two points, and you shouldnt get more than 1/2amp from the radio and voltage used by the computer. If theres more, theres something on somewhere. .



I assume you have taken a wire brush to your battery posts and terminals? Thats the first and easiest place to start. .



good luck



-j