no power anywhere

[ensign42]

Hi all-

This is a last minute hail marry. I went to help my boss out today- he has a 96 Bronco. It has had a lot of starting problems in the past, new starters, new ignition relay (passenger side fender relay), new battery, etc. It still did not want to start after it rained. So off I went. Last repair was to solder up the small signal wire that ran from the ignition relay to the starter. I listened to it for about five minutes, and heard the description, no start if it's to moist, after it gets warm it fires up. etc, etc. So- off I go to replace all the battery connections. I replaced- the negative cable from the battery to the block- and a small branch up to the fender well ground stud as well. The local parts store did not have anything like the factory positive cable, so I put a marine style terminal on the positive side, with one large cable down to the starter and a second over to the ignition relay. Threw it all back together and to ensure it started on the first try I threw my jumpers on post to post. Let it charge for a couple and said fire it up- well.... the first thing we noticed was no dome light- thought it may be a fluke. So I said try it anyhow- low and behold no power- not to anything- no radio, no headlights, no blower, no nothing. I had to run at that point to get my son from day care, so I am left wondering- what the **** happened? What is that relay on the fender- he has replaced that twice in three years. What is the distribution board directly behind it? It is full of corrosion. and several loose terminals. The negative terminal down was corroded solid to a steel vacuum line just above the grounding post. I disconnected all the cables at once because I wanted to run everything back through the wire hangers down at the block grounding stud. Tommorow I will replace the signal wire from the ignition relay down to the starter as it has been spliced three times now. Anything else you can think of that would cause this total loss of power? By the way when I test with a multi-meter I get the following with jumpers attached....

Battery terminals- 13.8 V

Positive to clean metal- 13.6 V

Positive to ignition relay input post- 13.7 V

Thanks all- and feel free to e-mail oppinions- ensign42 on yahoo.com

Will

 

[Broncobill78]

Will,

first off, I'm sure one of the other guys will backstop me on this because end-model Bronco's are NOT my Forte' but ****, a truck is a truck is a truck and ignitions haven't changed THAT much from the 78/79's that I DO know. hopefully SeaBronc or JSM84 will weigh in here. If I'm following this correctly the "relay" on the fender that you mention is the starter solenoid (Ford puts it on the fender to keep it away from exhaust heat, Chevy usually bolts it directly to the starter). If it's the Solenoid it *should* have a cable running FROM the positive battery terminal TO the solenoid and then FROM the solenoid down TO the starter. These connections freqently go bad (but you sould like you already understand your $hit so I won't lecture) but when they do typically you have all your lights & accessories *until* you turn the key & then the solenoid clunks and it all goes away.

Now you talk about a distribution board & admittedly the newer ignitions are now what I play with but it sounds like the ignition module. I *also* know that the aftermarket ignition modules are generally of fairly poor quality and people who hate replacing parts year after year generally pony up for the genuine Ford replacement parts (even NAPA & the other higher end vendors are getting $hitty replacement parts that aren't recommended).

However, if your boss has *nothing* then I would suspect a problem in primary power distribution rather than the ignition circuit. I maybe need to reread your post a second (or third, I'm slow) time but if I was the guy standing there in the rain I'd be looking at all of the primary cables & their terminal ends as well as the *ground* maybe adding a second ground to the frame or engine as opposed to just the fenderwell. Just my $0.02.

 

[ensign42]

Just to recap- less story- more details-

1- battery, newer (less than 12 months)- good charge, good elect. levels.

2- new solenoid on fender (less than 7 months)

3- new negative cable (> 24 hrs.) grounds to engine stud down near the pan and pass. side fender directly behind headlight.

4- new positive cable (> 24 hrs.) to solenoid on passenger fender- front post- only cable on this post

5- new positive cable (> 24 hrs.) to starter (top post)

good continuity on ground, demonstrated by multimeter reading of 13.6V between battery positive and freshly cleaned metal above radiator.

good starting power, demonstrated by multimeter reading of 13.8V on battery terminals.

good continuity to first post of the relay to the battery by multimeter reading of 13.7V from multimeter.

Based on those readings I think I have a good enough ground to at least make things light up a little..... so here are the real questions.....

Positive power has to get from the two cables I connected to the rest of the truck somehow..... I don't assume it does this from the main line to the starter, and I know Harry Potter is in Hogwarts right now. This leads me to- the power has to go through the relay somehow. Either I have wired the relay backwards (I really don't think so), the relay is not functioning, or that the distribution board connected to and directly behind the starter relay that is full of corrosion and crappy connections is used to route to ECM and fuse box type applications.

I am leaning towards the distribution board and possibly the multi-piece signal wire to the starter. If either or both of these is the culprit, problem solved fairly easily. I can see if that is the main distribution point for the rest of the vehicle, including Fords early ECM, it would prevent starting and **** all the accessories.

But, if that relay cuts off power to everything while cranking- it could have failed while we were dicking with everything else, it is a cheap after market piece. I imagine this is sort of a two way relay with no signal it sends power to the whole vehicle system, when signal is applied it diverts all power to starter.... right? Is there a way it could have suffered a catastrophic failure, meaning power cut off to everything, and not diverting to the starter? Is there a way to bench test this item?

I leave to take the wife and kids home for the holidays in 24 hours and would like to have him to the point I could talk it out over the phone if I can't get it done tomorrow.

Thoughts? Even if they include the term idiot- I'm open to opinions. >

Thanks!

 

[Justshootme84]

If you have NO power anywhere in the vehicle, it's normally a blown fusable link. JSM84

 

[Broncobill78]

Well, not to sound foolish but the solenoid *does* cut power to everything else and if it's been replaced repeatedly (maybe with an AutoZone quality part ?) then it may still be the problem. Also, the fusable link suggestion is a good one. It's only happened to me twice but both times it was a bitch to track down until I sat down & started thinking it through.. Have you checked the links ?

 

[ensign42]

I have no idea about the fusable links, boss has a manual, I will look them up when I get there. Where do I find them located?

Will

 

[ensign42]

Problem found- ignition wire to starter relay! Fixed and back to full function! Thanks all!

Will

 

[Justshootme84]

Glad you found it!!! The previous owner of my 84 Bronco had spliced theat wire with some speaker wiring, which kept burning through when it got hot. The fusable links are the other two (or three) wires going to your starter solenoid. they often have a square block looking deal near the end. they will also say "fusable link" printed along the wire. they're designed to basically burn in half when you have a major short, so it protects the rest of your wiring and circuits. And I normally went through 2 or 3 solenoids every year on my 84 Bronco. Make double sure the battery cables are good, since thtey can and will corrode from the inside. Also, make sure you have a good, clean ground to the engine and the body/ frame. JSM84