Electrical adventures thread - I blew or burned out something...

WMO4IDI

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Well, what started out as a fun electrical project turned to crap. My '89 F350 has had lots of mods done to it, mainly a big rig sleeper cab installed & lots of lights... so many unholy electrical splices done under the dash by POs and it bit me in the ****.

The two main projects I was working on were redoing a custom switchboard & installing a new remote entry system.

The switchboard on the dash controls 6 things: position lights, amber cherries, aux. backup lights, interior lights, fuel tank/line heaters & heated mirrors. This project is done & over with now... although I wanted to bang my head while looking at the PO's wiring, no relays anywhere, full power going through all the switches, splice upon splice with not much color coding of wires... heres a crappy picture of the back of the original switchboard:

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I bought a 6 fused relay box & some marine rocker switches to remake all of this as properly as possible. The relay box sits beneath the glove box by the ashtray, I have one 6 wire harness connecting the switchboard above the heater control to it.

I'll post more pics when the dash is back together.

Now for the fun part, the remote locks...

Putting in an avital 3100L remote to replace the old defective chinese black box so I did my homework, 5 wire system, need dual relays for a polarity inversion setup to not blow up the keyless entry controller, bla bla bla... got it all setup & hooked up to the existing actuator wiring. Unlock was functional, not lock.

I blew a 15amp fuse feeding the manual switch while playing with it repeatedly, heard a loud pop, swapped it out, blew it again & realized that the actuators were burned out. Pulled one out & tried it on a 12vdc power supply, no clicky at all.

Now here's the kicker!

The original aftermarket power lock 12V+ feed... was piggy backed by inserting a spade connector into the #11 fuse slot Yanked that out right away.

When I turned the key to acc. & to run, I had no power going to illumination nor the radio/heater unit.

Pulled all the fuses but they all looked fine, none burnt.

If the fuses look good and I didn't smell any burnt wiring as far as i can remember, would I be right to assume that I might now have an ignition switch or connector issue? The truck doesn't have a fender mount fuse box, just the one by the steering column. According to the wiring diagram the Black/Lt Green wire coming from the switch feeds fuse #11 and subsequently the radio & dimmer switch feed. I loath having to test the ignition switch for continuity...

Anyways, I ordered new door lock actuators, switching to a simpler 2 wire system & redoing all the wiring (could be a short somewhere). Soon I'll have a functioning alarm system & power door locks, woot! Who needs instrument lighting, a radio & hvac...
 

WMO4IDI

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Previous owners and geellectric :frustrate
I pulled out 2 shopping bags of primarily exess trailer harnesses outta my 88
Luckily I didn't have too much excess clogging everything up, just a bunch of splices with wires going everywhere so everything's tightly tangled up inside the dash.
 

franklin2

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Nothing wrong with running full power through switches if the wiring is large enough and protected with a fuse, and the switch is large enough for the load also.
 

WMO4IDI

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Did you check the fusible links under the hood by passenger fender? One of those is a feed.
That's definitely on the list of things to check out. The wiring diagrams don't shows 3 or 4 from the solenoid, I got to that part after writing the post.

Do they age? Should I swap them all out as preventive maintenance?
 

hacked89

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That's definitely on the list of things to check out. The wiring diagrams don't shows 3 or 4 from the solenoid, I got to that part after writing the post.

Do they age? Should I swap them all out as preventive maintenance?
No to preventative maintenance. Sometimes people cut them out and put a breakout fuse box in its place. I’ve done it both ways. Don’t feel strongly about either. Once I do blow link(s) though I replace with a fuse box.
 

WMO4IDI

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Nothing wrong with running full power through switches if the wiring is large enough and protected with a fuse, and the switch is large enough for the load also.
Fair enough, when I encountered burnt spade connectors & wires I just decided to not have all that power snaking through the dash & keep everything easily accessible.
 

WMO4IDI

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No to preventative maintenance. Sometimes people cut them out and put a breakout fuse box in its place. I’ve done it both ways. Don’t feel strongly about either. Once I do blow link(s) though I replace with a fuse box.
Good idea, keep it simple & accessible!
 

nelstomlinson

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I guess the factory uses the fusible links because they're cheap? They're a needless pain in the behind now, though: tough to troubleshoot, a nuisance to replace.
 

ihc1470

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I find they are usually in circuits that need protection but as a rule will never have an issue that would cause one to blow. Such as feeds coming off the main power sources. Those systems (lights, gauges, etc.) are normally protected by fuses and the links provide the protection for the feed circuits to the fuse panel.
 

franklin2

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I guess the factory uses the fusible links because they're cheap? They're a needless pain in the behind now, though: tough to troubleshoot, a nuisance to replace.
Fusible links are cheap. But they are also small and fit easily in a crowded wiring environment. And they give very little trouble. I would say 99% of the time a fusible link blows because of a accident or a owner making the wrong decisions and not disconnecting the battery during certain maintenance.

Fuses are large and take up room compared to a fusible link. And then corrosion becomes a factor also. The factory to this day, even if the vehicle has a underhood fuse box, still uses fusible links in some of their wiring.

A fusible link consists of a undersized piece of wire, with special fire retardant insulation around it so if it blows it won't catch anything else on fire. It's very resistant to nuisance blowing and can take a lot of amperage before it does burn in two.
 

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