parasitic drain, fuse pull test was no help

[Mike Wilson]

I have a 1985 Chevy S-10 pickup. 2.8 V6, automatic. I have a 4.7 amp parasitic draw. the battery goes dead in 2 days. I have replaced the starter, alternator, and battery. all are new. I did the draw test by pulling each fuse one at a time. no changes in the draw. I removed every fuse and everything plugged into the fuse box all at once and still the same draw. I unhooked the alternator, same draw. I unhooked the starter, same draw. I unplugged every relay under the hood and same draw. I don’t know anywhere else to look. Any help would be greatly appreciated!! Thank you. Mike

Topic

[Mike]

I know it could probably be assumed, but could you clarify if there are any aftermarket electronics on it and which terminal/post you have the meter in between. I’ll look up the wiring diagrams at work tomorrow and see if there are any circuits other than what you mentioned or that would be hard to detect by physically looking at it. Hopefully I can find something.

[Mike Wilson]

I had all of the aftermarket stuff (cb radio, driving lights, running board lights) unplugged from the fuse block when I did the test. My digital meter was between the negative cable and the negative battery post. It showed 4.70 amp draw. I also tried it backwards. I put the negative cable back on and tried the positive side. Same reading. I unhooked the starter, same result, unhooked the alternator, same result. I unplugged all of the relays under the hood that I could find. Same result. I even unhooked all of the electrical gauge sending units from the engine. Same result. Thank you for the reply and any help you can give. Thanks, mike

[Cameron]

[quote=”rogueleaer” post=114854]I had all of the aftermarket stuff (cb radio, driving lights, running board lights) unplugged from the fuse block when I did the test. My digital meter was between the negative cable and the negative battery post. It showed 4.70 amp draw. I also tried it backwards. I put the negative cable back on and tried the positive side. Same reading. I unhooked the starter, same result, unhooked the alternator, same result. I unplugged all of the relays under the hood that I could find. Same result. I even unhooked all of the electrical gauge sending units from the engine. Same result. Thank you for the reply and any help you can give. Thanks, mike[/quote]

I don’t know how your 1985 truck is set up but in my late model GM car I could pull all the fuses and relays and it would not isolate 2 known areas of current draw, namely the seat motor for seat adjustment and the power windows. In my vehicle these are covered by dedicated circuit breaker fittings not by the usual standard block of fuses and relays.

I am aware of possible current draws occurring with faults from either of these items (ie. a faulty seat motor and a power window motor that continues to run due to a faulty switch). Given the age of your truck you probably do not have either of these items fitted though but I thought I would throw this up in case.

[EricTheCarGuy]

Do you have a bed light? You might consider taking the bulb out. It’s also important that you close the doors. Also, some of those older trucks had a light under the hood. You’ll also need to unplug this if that’s the case.

[Mike]

I’m sorry, I got too busy today and forgot to look at the wiring diagrams because I didn’t ever have a moment to check with the internet like I usually do. I’m still gonna try and do it tomorrow, as long as I have any time at all to look at my computer I’ll remember.

UPDATE

AllData didn’t have diagrams of power and ground distribution on that car, and I couldn’t find any other wiring diagrams that would tell me more than you probably already know. I did find a TSB that says that the computer might cause a draw only after it has been turned on and then off, so disconnecting the battery to set up the test gets rid of the draw if it’s that. The TSB states that after you hook up your Ammeter and jumper wire between the battery post and terminal, switch the ignition on (DO NOT START) and then off again.

Obviously you are not having this problem, but I thought it would be of interest and useful for you to know about. Sorry I couldn’t be more helpful.

[Author]

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