fussing and fighting with electrical after fusible link replacement

[swelltimes]

Last week, I realized that I didn't have a proper fusible link installed on my 6/77 FJ-40. I ordered up a replacement from @Coolerman, and installed it yesterday.

The starter engaged for a fraction of a second when I turned the ignition on, then all electrical went dead: no lights, no starter motor, nothing. Checked connections, still nothing.

This morning, I disconnected the new link, and jumped from the + terminal to the harness (which was essentially what the PO had done), and still nothing.

I'm getting 12+ volts at the battery, and all the way through the new fusible link, into the harness. For installation of the new part, I cleaned the battery post and terminal; stripped a new section of the white wire going into the harness; used the supplied connector to attach the link to the harness; used some dielectric grease on the connection of the link to the battery terminal.

I briefly checked fuses, and they look intact.

So, looks like I've got some troubleshooting ahead of me.

I wonder if the PO put some sorted of fuse / fusible link somewhere else in the wiring harness that I popped when I installed the new part?

Anyone else have a similar experience?


1st pic is of the set-up I just replaced.

2nd pic is of the connector that was being used:

3rd pic shows similar set up on - terminal (which I left alone):

4th pic shows how I terminated the + lead from battery terminal before installing new link:

5th shows new link installed:

 

[HawkGunner]

Did you check resistance and starter draw?

 

[swelltimes]

Did you check resistance and starter draw?

No, I didn't check resistance. I'm not well-versed in electrical issues, so I assumed that if I was getting 12v thru the link, I'd be good to go.

I'm assuming you're talking about resistance thru the new link?

Can't test started draw until I can get this first issue solved, I believe.

 

[HawkGunner]

Check for source voltage at the starter. If you don't have source voltage, find out where along the line you're losing it, then fix whatever is causing it.

Start by cleaning the corrosion and rust off everything.

Test for resistance and continuity through the fusible link you installed. Just because it looks like it's intact, doesn't mean it is anymore. It's likely that the PO deleted the link because it kept blowing... which would indicate an improper ground somewhere.

 

[mtquivr]

I briefly checked fuses, and they look intact.

"Looking" at fuses doesn't prove they're not bad. Save yourself time by checking them with a meter or test light.

 

[samatulich]

Here is what I found when I had to replace my fusible link. I had some resistance at the ignition switch 4-wire plug. The four wires that start at the ignition switch, run down the steering column and plug into the wire harness under/behind the instrument cluster. The Blue/White to Red/Black wire connection was shot. I didn’t have the proper 4-wire plug, so I simply connected the wires individually. Anyways, you might take a look, mine was quite oblivious.

 

[swelltimes]

Thanks for the suggestions, all. I'll start working through that list when I get some shop time later this week.

In the meantime, I came home from work earlier today to get started on some troubleshooting, only to find that the lights were on (I forgot to turn off the switch, since they weren't working), and had drained the battery a good bit.

Battery is charging right now.

 

[HawkGunner]

Thanks for the suggestions, all. I'll start working through that list when I get some shop time later this week.

In the meantime, I came home from work earlier today to get started on some troubleshooting, only to find that the lights were on (I forgot to turn off the switch, since they weren't working), and had drained the battery a good bit.

Battery is charging right now.

I used to be famous for leaving the headlights or dome lights on, or locking my keys in the car.

This might sounds silly, but I found it helpful to develop a checklist for startup and shutdown, similar to what we used as a helicopter crew in the Army.

Maybe a little redundant and drawn out to some, but I never drive off anymore without having adjusted my side mirrors or having checked my oil etc. And I never walk away now with any lights or power sources left on or the doors unlocked and without my keys in hand.

 

[swelltimes]

Made some time to get out and work on the truck today.

So, in my 6/77 FJ-40 (CA spec), I believe the fuse for the ignition system is 2nd from the bottom of the block, and should be 15A. Correct?

I pulled the fuse out of that spot, and it's rated at 30A....

Thoughts? Replace it with the 15A fuse, yeah?

 

[spotcruiser]

Yep, my '76 CA truck has a 15a fuse second from the bottom labeled "Ig.Coil". That's misleading, since the ignition circuit is not fused. The W/D labels that circuit "Engine". All I see on that circuit is the Idle Solenoid, emissions, and carb cooling fan. 15a should be more than enough for that circuit. Install a 15a fuse and see what happens.

Made some time to get out and work on the truck today.

So, in my 6/77 FJ-40 (CA spec), I believe the fuse for the ignition system is 2nd from the bottom of the block, and should be 15A. Correct?

I pulled the fuse out of that spot, and it's rated at 30A....

Thoughts? Replace it with the 15A fuse, yeah?

 

[swelltimes]

Yep, my '76 CA truck has a 15a fuse second from the bottom labeled "Ig.Coil". That's misleading, since the ignition circuit is not fused. The W/D labels that circuit "Engine". All I see on that circuit is the Idle Solenoid, emissions, and carb cooling fan. 15a should be more than enough for that circuit. Install a 15a fuse and see what happens.

Right, I'll give that a try, then.

 

[spotcruiser]

I just now read the whole thread. My post #10 above only addressed the "Engine" or "Ign" fuse issue. As noted, that fuse should be 15 amps.

That fuse issue is not related to the non-start problem. Do you have a wiring diagram?

 

[swelltimes]

Yep, I do have a wiring diagram, but I don't have a lot of experience chasing electrical issues. So, learning as I go here, with the help of the forum and my FSM.

I checked and cleaned the 4-wire connection from the ignition switch into the wiring harness, but no change after that.

 

[FJ40Jim]

So what electrical items are working?
What electrical items are not working?

 

[spotcruiser]

So, your headlights were on? You do have power to the fuse block to power the headlights?

 

[swelltimes]

So what electrical items are working?
What electrical items are not working?

Nothing is working. No lights, no starter motor. Battery is charged.

I turn the key, and get nothing, aside from a slight twitch of the ammeter needle.

 

[spotcruiser]

In your third photo above do I see a fusible link from the battery neg to ground, in parallel with a frame ground and a (I assume) a block ground? You can get rid of that. That fusible link on the battery neg does absolutely nothing in parallel with the other two grounds.

 

[spotcruiser]

Well, if your ammeter moves, it's not burned open.

I'd disconnect the battery and look at the back of the fuse block. The terminals are riveted and they can loosen and/or corrode and overheat. You may find bad connections there.

Nothing is working. No lights, no starter motor. Battery is charged.

I turn the key, and get nothing, aside from a slight twitch of the ammeter needle.

 

[FJ40Jim]

In post #7, the lights were working. Now nothing is working. Has anything been changed on the truck between then & now, or did they just stop working one day?

 

[swelltimes]

In post #7, the lights were working. Now nothing is working. Has anything been changed on the truck between then & now, or did they just stop working one day?

Correct - lights no longer work. I haven't changed anything since then, aside from checking that plug connection from the ignition switch last night.