1989 Isuzu Trooper Install solenoid to disconnect battery

Tiny
AL BARRS
  • 1989 ISUZU TROOPER

Electrical problem
1989 Isuzu Trooper 4 cyl Four Wheel Drive Manual 145000 miles

I have a slow batter drain in my hunting and farm SUV electrical system that I have been unable to locate. I am installing a Ford starter solenoid in the battery ground cable to disconnect the battery when I turn off the ignition switch.

Please tell me on which or both of the two smaller solenoid terminals I need to connect the ignition switch wire.

Does it make any difference which of the two battery cable terminals I connect the battery ground wire, block to solenoid and solenoid to battery terminal?

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Saturday, January 3rd, 2009 AT 7:43 PM

18 Replies

Tiny
BUDDYCRAIGG
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If you put the solenoid in. Then the ignition switch isn't going to have any power to energize the solenoid.

You will have to run independent wires from the battery to a toggle switch and then to the solenoid.
And the solenoid will still have to be grounded to the battery.

But to answer your question, you would put the exciter wire on to the post next to the letter "S"

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Saturday, January 3rd, 2009 AT 10:26 PM
Tiny
AL BARRS
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Buddy;

I am sending a diagram I drew for wiring the battery disconnect circuit. Is this what you suggested and Is it what I need? THANKS!

Let me know if you didn't get the diagram. I can't see if it uploaded or not. Thanks

Al

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Sunday, January 4th, 2009 AT 5:26 AM
Tiny
BUDDYCRAIGG
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I applaud your efforts but the way you have it.
the two grounds i have circled will not be grounded.


http://myfiero.com/uploads/15099_.jpg


.
.
i'll be right back.
.
.
try this.
and be sure the solenoid you get is rated for "constant duty"
and keep in mind, if you have any problems with the contacts in the solenoid, everything in the system will try to ground through that little switch


http://myfiero.com/uploads/15100_.jpg

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Sunday, January 4th, 2009 AT 6:07 PM
Tiny
BUDDYCRAIGG
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I guess you are against the idea of using something a little low tech.
like


http://toolmonger.com/wp-content/uploads/2008/07/BatterySwitch-450.jpg



or


http://www.outbackers.com/forums/uploads/1154134718/med_gallery_2363_3_32210.jpg

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Sunday, January 4th, 2009 AT 6:22 PM
Tiny
AL BARRS
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Thanks for the reply Buddy! You are the greatest help I have found on the Internet.

I ordered one of the battery disconnect switches like you posted, but was concerned that I couldn't run a heavy battery cable into and back out of the cab to the battery and if I couldn't do that and installed the switch under the hood I would still have to remember to raise the hood each time I stopped to turn off the battery disconnect switch. The length of battery cable stopped me from this idea that even I had though of as a first and easy fix.

Thanks for the revised wiring diagram I sent you!

But, I now have a different problem and have decided the best move for now is to put everything back to original and keep raising the hood and removing the negative battery cable to prevent the slow battery drain from killing my new battery. I need to use the vehicle for a couple more months and it will mostly sit over the summer until later this year. Here is what is going on now.I'll start from the beginning.

The problem started with a slow battery drain that would run even a new battery down to zero over several days sitting time.

First as you suggested then, I removed the negative battery cable from the battery. Using a 12-volt test light, I hooked one end to the negative battery post and hooked the other end to the negative battery cable I had disconnected.

You said that the test light will glow or "light" if there is an electrical drain. You said, if the "light or glow" is faint, that is probably normal draw for the clock or computer, I was told. And I was told, if the "light or glow" is bright, then there is a large electric current drain. That circuit could then be troubleshot and corrected or isolated to stop the battery drain.

I then removed and replaced the fuses one by one looking for the test light glow to go out knowing that the one that distinguished the bright light would be the circuit with the battery electric drain.

Unfortunately, the test light never went out.

Second, I tried to install a Ford solenoid in the negative battery cable circuit from the negative side of the battery to the engine block ground bolt. I then tested the solenoid with a temporary wire from the positive terminal of the battery to the " S' terminal on the Ford solenoid, nothing happened. I then tried touching the " I' terminal on the Ford solenoid, nothing happened. I then attached a short wire from the " S' terminal on the Ford solenoid to the vehicle frame and tried again. This time a touch to the " S' Ford solenoid excited and activated the solenoid and I thought I was home free.

To make sure I hadn't blown a fuse, fuseable link or something I put the wiring configuration back (original) as it had been before I installed the Ford solenoid in the negative ground battery cable and got in the vehicle and started the engine. It ran fine.

At this point I believed that all I needed to do was figure out how to connect a circuit from inside the vehicle from the dash to the Ford solenoid to excite the solenoid and energize the starter system so I could then turn the ignition key to start the engine.

I drove my wife's car to town to buy a toggle switch and a roll of wire to make the connections. When I got back I had a call about something that required me to use the Trooper to pull a small trailer so I first checked that everything under the hood was back in it's original place and disconnected the Ford Solenoid and the extra wiring I had done earlier.

I connected the original Isuzu negative battery cable and got into the cab and inserted the ignition key. When I turned the ignition key all the dash lights and instruments activated normally, but when I tuned the key to the start position absolutely nothing happened. There was no starter Isuzu solenoid click, no starter grind and no dim lights. Nothing. All was quite!This made me believe I had somehow blown a fuse, perhaps the ignition fuse. I check the fuses and could not find any that had burned out. Now I am at a loss as to what went wrong or what to do.

I have the wiring back to the original Isuzu configuration with the Ford solenoid and its wiring disconnected and isolated so there is no influence on the original Isuzu starter wiring circuit configuration.

WHAT MIGHT HAVE HAPPENED THAT THE IGNITION SWITCH DOESN'T EXCITE THE ISUZU STARTER SOLENOID NOW?

I tried to get to the starter to directly excite the starter solenoid to see if it was working but haven't been able to get my vision or hands to it because of the closeness. I suppose the vehicle has to be on a lift to get to the starter. FRUSTRATED!

Can you suggest what might have happened to the original Isuzu starter circuit to render it inoperable now?

Forget about the Ford solenoid for now! I just need to get her back running for a couple of months and can then figure out how to either locate the battery drain circuit or install the controller Ford solenoid.

Thanks very much for all your help,
Al

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Tuesday, January 6th, 2009 AT 7:54 AM
Tiny
AL BARRS
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Buddy;
I checked for continuity with my ohm meter and determined that there was continuity between location A and Location B in the following wiring diagram you modified. A and B are marked in GREEN. I am of the opinion that this would direct positive current to the ground on the Trooper's frame. Am I wrong?

Thanks,
Al

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Tuesday, January 6th, 2009 AT 10:31 AM
Tiny
BUDDYCRAIGG
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Yes, A and B would have continuity because of the coil windings of the solenoid.

But when the solenoid is at rest, the frame is not grounded. Because it's not connected to the battery.

That is why I added the black wire and used a double pole switch.

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Tuesday, January 6th, 2009 AT 12:00 PM
Tiny
AL BARRS
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Thanks Buddy:

One more question, since the solenoid (I have a Ford solenoid) will be engaged while I am driving the Trooper so that the battery ground is complete or connected will I need to use a constant duty solenoid? Will the Ford solenoid overheat if left engaged during driving for an hour or more so electric power is supplies to all the circuits, like lights, radio, heater blower, etc?

Now all I have to do is figure out why the Trooper II doesn't turn over when I engage the ignition switch. I suppose it has to be either a fuseable link or a fuse that I haven't located yet. Or, I guess the starter solenoid could have burned out. What do you think. When I turn the ignition key the dash lights and gauges light up OK but when I turn it to the start position I get nothing at all, no dimmer lights and no starter solenoid click or starter whine. The battery is new and fully charged.

Thanks,
Al Barrs

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Tuesday, January 6th, 2009 AT 12:39 PM
Tiny
BUDDYCRAIGG
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I did suggest that you used a constant duty solenoid in one of my earlier posts.
If you will tell me what auto parts stores are in your area, i'll get you some common part numbers that are rated as such.

About the no-crank.
It's just going to take some good old fastened testing.

First I would use a test light to make sure the exciter wire was getting power at the starter solenoid when the key was turned. (Use a test light, a meter can read 12 volts, even if there isn't many amps and could lead you down the wrong path.)

you mentioned that it's a tight fit up in there, you can attach the ground clip on the solenoid stud and then touch the test light probe on the frame and it will still work.

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Tuesday, January 6th, 2009 AT 2:23 PM
Tiny
AL BARRS
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Thanks Buddy;

I will try using the test light to check but I haven't been able to find a separate starter solenoid on the '89 Isuzu Trooper II unless it is a different shape than what I am used to seeing on American vehicles and I will defiantly use a continuous duty solenoid instead of the Ford solenoid.

I found an Imtra Corp. Continuous duty solenoid on the Intrnet but haven't found a store near me that sells it yet. It is an IMTRA 12-Volt Continuous Duty Solenoid Mfr # SPA10600. I sent their tech support person a question about extended continuous use while activated but haven't heard from him yet.

We have AutoZone, Auto Value, O'Reilly's, Carquest Auto Parts, Advance Auto Parts and Napa Auto Parts

Thanks,
Al

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Tuesday, January 6th, 2009 AT 2:52 PM
Tiny
BUDDYCRAIGG
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Call your napa and see if they have one of these
Echlin ST80, It would be safer for how you want to use it.

And i'll have to redo your diagram cause it's wired differently.
.
You have a gear reduction starter and it probably looks different than what you are used to.

I can't draw any arrows on pics at work, so i'll have to try to explain what you are looking at.

The upper, big cylinder shaped thing is the actual motor,
that little black tail thing pointing down is a rubber drain tube. Pay no attention to it.

The left side is where the gear reduction is.

The black retangle thing on the bottom is the solenoid.

Looking at the solenoid, you can see the stud for the battery cable in the lower right corner.
Directly above the stud is a spade terminal inside a plastic connector.

The energizer wire connects to that spade terminal

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Tuesday, January 6th, 2009 AT 4:13 PM
Tiny
AL BARRS
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Thanks Buddy!

I sure haven't seen a setup like that and it helps me locate the contact point to test.

Thanks!
Al

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Tuesday, January 6th, 2009 AT 4:40 PM
Tiny
AL BARRS
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Thanks Buddy!

I sure haven't seen a setup like that and it helps me locate the contact point to test.

I will await your schematic drawing changes before proceeding with installing a solenoid control.

I need to first get the Trooper running again before installing the continuous duty solenoid and toggle switch.

I will keep you posted.

Thanks!
Al

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Tuesday, January 6th, 2009 AT 4:42 PM
Tiny
BUDDYCRAIGG
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Call napa and make sure they can get that part number before I go through the trouble or redoing the drawing.

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Tuesday, January 6th, 2009 AT 5:01 PM
Tiny
AL BARRS
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OK, I will call NAPA tomorrow morning and get back to you on the Echlin ST80 solenoid. Thanks!

Is NAPA part #ECHST85 essentially the same part? They have that on their Website but I haven't called locally yet to see about the ST80. It is an insulated solenoid though and has copper contacts:
For 12 Volt Systems
Continuous Duty
80 amp.
Insulated Base
Flat Bracket
Coil 16-21 Ohms. Same As ST80 Except Has Copper Contacts.

Al

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Tuesday, January 6th, 2009 AT 5:46 PM
Tiny
BUDDYCRAIGG
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Yes the ST80 and ST85 are the same except for the contacts. and is cheaper.

I choose it because it's insulated.
so if you have a continuity problem in the solenoid, the trucks electrical system wont try to ground through that little wire.

i couldn't find a DPST switch that napa keeps in stock.
but i was using my part numbers as i didn't have their book to look through.

here's the updated pic.
notice the little green guy is a fuse. (i thought about tapping into a circuit that is always "hot" in the fuse box, but you already have some mystery electrical problem, i want to leave the trucks harness alone.)


http://myfiero.com/uploads/15110_.jpg



speaking of your mystery electrical draw.
did you happen to unplug the alternator when you were using the lightbulb as a make shift amp meter?
You may have guess by now that electrical is one of my strong suites, not finding a draw would be unacceptable to me.

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Tuesday, January 6th, 2009 AT 6:52 PM
Tiny
AL BARRS
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Good morning Buddy!

Yes, I disconnected the Alternator but still couldn't find anything. I would desperately like to find the electrical battery leak and have spent over a year on and off searching for it. First I thought it might be the rear dome light but I took out the bulb for a while and that wasn't it. If I could find the circuit that is grounding I wouldn't need to do all the other stuff to isolate the battery when I am not driving the vehicle. I am not an expert with motor vehicle electrical systems but do understand a little about basic electrical theory. When I disconnect or connect the negative cable to the battery I can hear a relay clicking in the fuse/relay box but haven't been able to determine just which one is doing the clicking. I do believe it is one of the circuits that is on a relay, but the electrical wiring diagram has so much interconnected wiring it is difficult for me to read and make a lot of sense of.

Al

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Wednesday, January 7th, 2009 AT 5:17 AM
Tiny
BUDDYCRAIGG
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Have someone disconnect and reconnect the battery while you are searching for the relay.

Most of the time you can rest your hand on them and feel which one is clicking.
Or start unplugging them until you dont hear the clicking anymore.

Tell me which relay it is and i'll take a look at the schematic for a possible cause.

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Wednesday, January 7th, 2009 AT 7:56 PM

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