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Discussion Starter #1
I have an electrical problem with my '89 Bronco. Out of nowhere the battery started to drain down if left unstarted for awhile, normally the truck would sit regularly for one to two days at a time without being run and would start up with no problem. Now if left for a couple of hours( 6 - 8 ) the battery is stone dead. First I thought, bad battery, so I put in a new one, same thing. Now I thought there's a problem with the alternator, but while running it charges just fine even at load. So this lead me to believe there is a short in the system. So i try the old fashioned approach, I remove the negative cable from the battery, and run the tester between the post and the cable, even disconnected it shows voltage, A-HA there is a short! So I start to pull one fuse from the fuse block at a time til the tester shows no voltage, go thru them all, still showing voltage, DAMN!!! Next I remove all the fuses, turn signal flashers and circuit breakes from the block, still showing voltage, AAARRGH!!!!!!. So now I put the fuses etc, back in their right spots, now it's time to attack the starter relay/solenoid. There were three yellow wires and one bluish-green wire, didn't have a no-show on the meter til all were off the solenoid except for the main battery cables. No more power drain, but no starting the vehicle(DUH!). Now the bluish wire goes to the alternator, and the wiring diagrams list the yellow wires going to fuse #1(stop/hazard lights & speed control), EEC power feed and the ignition switch. Problem is they don't specify which goes where!!!! All three are yellow with NO STRIPES OR NUMBERS!!!! The only difference in the wires is size, one small, one medium and one large, and yes I did clean the wires thoroughly to make sure there were no markings. Now I would really like to resolve this problem at home and not take my baby to a shop, but i'm at wits end, can anyone out there help me solve this riddle, or should I just do the sensible thing and go to the shop??? Any and all help is GREATLY appreciated.


<font size=-1>[ This Message was edited by: MHumpy on 1/24/02 5:27am ]</font>

<font size=-1>[ This Message was edited by: MHumpy on 1/24/02 5:28am ]</font>
 

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I don't have the answers but maybe it can be figured out.

Logic would dictate that the largest yellow wire is your starter feed.

The medium is most likely your lights.

The smallest is the EEC power.

If you have a multimeter you should be able to determine which connecter energizes the solinoid. (Should be the only lead that grounds). You can check if the large wire is indeed the ignition switch by turning the key and see if power is going to it.

You have a 50/50 chance on the other two!


The lights should be hooked up to the lead with "constant" power.

Both the EEC and Lights might be constant, then I would think it wouldn't matter which spot you hooked them too.

Hopefully someone else will join in...

GOOD LUCK!!!


_________________
1965 Falcon 289 C4 Hardtop
(After I finish the 6 to 8 swap)

<font size=-1>[ This Message was edited by: 1965FALCON on 1/24/02 5:57am ]</font>
 

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I've seen alternators drain battery's before even though they still charged the battery when running.Don't rule it out just because it appears to be charging o.k.There's nothing worse than sortin through the spaghetti trying to find where wires go.Good luck
 

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Discussion Starter #4
Got the truck running long enough to get it down the street to a decent shop, by time they got to it they said it didn't look good. At that point the computer was completely smoked, alternator shot, starter relay fried and the battery was a lost cause.
My mechanic said it looks as though someone else had been into the system before, so he's going to try and check for other shorts elsewhere. All things considered, parts and labor, and about three days of waiting and i'll have my truck back and only have to shell out about $700 bucks.
 
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