75 keeps blowing 15A engine fuse

[bhsdriller]

Cruiser is a 75 with a 2f from a 78.

I need help with what is ran through this fuse. I know the main thing is the idle solenoid because it wasn't clicking/getting power. I started looking around and saw that the fuse holder was rigged or something. I can wire the solenoid to battery power and it works perfect, cruiser runs good.
Not very good at diagrams and i've been looking.
Fuse holder has been replaced and it pops right when key is turned.

 

[bhsdriller]

I know something on the circuit is shorting out but need some help with wiring diagrams to figure out what to check.

Thanks in advance

 

[DoubleNickels]

@Coolerman has gifted us all with schematics. Find your year and review:

Coolerman's Electrical Schematic and FSM File Retrieval

It goes without saying that your entire fuse block looks haggard. I see some bent tabs and the one terminal that's broken, probably worth checking them all.

 

[bhsdriller]

Yep fuse block is done. Its already been replaced

 

[Solace in Solitude]

IIRC, based on earlier posts and pictures, your wiring harness had a lot of issues. I think it’s the one that had blue spade connectors and a main wire with the insulation melted off.

Am I remembering correctly?

If NOT, please disregard

You have a ‘75, with a ‘78 engine... have you figured out what harness you have?

Have you traced wires and fixed your harness? To match what schematic?

Its not easy for us to help without knowing what harness you are using and what modifications have been made to it.

Perhaps you can post pictures of the front and back of your NEW fuse box, annotated to show which fuse is popping?

IIRC you were popping the engine fuse, when you first posted a picture of the wire, with the melted insulation... if you haven’t replaced that wire, it’s probably shorting out and popping the fuse.

 

[ToyotaMatt]

This is really simple here the minimal physical contact between the glass tube fuse end cap , and the 1 broken fuse holder and some P/O JERRY RIG

strand wire twist B/S has caused a electrical Flood Gate or DAM if u will of

current flow and amperage , so what happens when this occurs :

the Water Spills over the Dam or Dike , and hence blows the Fuse ,

as it it is Properly designed to do , this is normal , The fuse blowing part


be VERY greatfull it did and your harness and or connectors are NOT fried and

melted too .............



- well He#l after all it's officially X-mass EVE 2019 !


@bhsdriller ,

Please review the photos below , and pick out your New

Fuse holder of your choice , to be VERY clear ALL these are in A-

condition in every way and WILL serve you well , also simple plug and play

same as yours via the green and black spade connectors on back sides


also , if they match , a matching Fuse Box cover of your choice , i have 3 of

those , the center one is NOS , the 2 outer ones are A- condition as well ,


i will be happy to simply mail the parts out to you as professional Samples

with NO cost to you involved , i have USPS priority mail 2 day shipping

covered as well ........................

please PM me your shipping address after you decide witch ones you like !



Kindly Matt ,

 

[ToyotaMatt]

also ,

you need to check VERY carefully the Terminals inside the 2 fuse box connectors

that carry at that blown 15A fuse you have , this requires extracting the

Terminals , and inspecting the crimp of strand wire and the wire and terminals them selves too ,

i have seen this scenario many times , and u Cannot diagnose from outside

connector housing , must pull out via a terminal pick properly Verify

and possible repair ......


see also if the green or black connectors show signs of melting outer in the

15A terminals bays in questions ......

 

[bhsdriller]

@Solace in Solitude I had some small issues with the wiring but it wasn't major. Don't think you're thinking of me.
I'll get some pictures right now.

@ToyotaMatt I greatly appreciate the offer but i'm going to have to decline. I'd feel bad taking them with just purchasing a new one. Let them go to someone else.

I'll check those wires/connectors that you mention.

 

[ToyotaMatt]

@Solace in Solitude I had some small issues with the wiring but it wasn't major. Don't think you're thinking of me.
I'll get some pictures right now.

@ToyotaMatt I greatly appreciate the offer but i'm going to have to decline. I'd feel bad taking them with just purchasing a new one. Let them go to someone else.

I'll check those wires/connectors that you mention.

ok , no worries

if u need the connectors by chance PM me there on Me as well ,

Xmass Eve 2019 ............

kindly matt ....

 

[bhsdriller]

Not the best pictures but the fuse that's blowing is the second one up from the bottom that's labeled "engine 15a". You can see the location on the above cover.

To add everything electrical works perfect on the truck (well besides this lol). Not sure what those unplugged connectors are. Later year harness?

 

[ToyotaMatt]

Fuel Cut Solenoids can Develop an short circuit inside , due to old age wear and tear

unplug your fuel cut at the carb , does the fuse still blow ?

yes , then you have another issue , i would then unplug your Green Ignition

switch at steering column , then install a new fuse , test your ignition switch on bench via FSM for internal shorts , resistance etc .......

its a moving parts inside product and fails internally copper contacts like a pull switch

start here , with the moving parts topics outlined above , if all good then

you have a wiring issue , if not then you have found your problem ...


good luck.........

matt

 

[bhsdriller]

Checked the easy thing. Unplugged idle solenoid and fuse still blew.

Looks like I have some trouble shooting to do.
Thanks again for the input

 

[Brian/99uzj100]

Not the best pictures but the fuse that's blowing is the second one up from the bottom that's labeled "engine 15a". You can see the location on the above cover.

To add everything electrical works perfect on the truck (well besides this lol). Not sure what those unplugged connectors are. Later year harness?

View attachment 2164965View attachment 2164966

Regarding the two unplugged harness connections in your pic:

On my 2/76 the larger one connects to the emissions computer, which would be mounted to that silver colored bolt right above it in your pic. Not sure about the smaller one.

EDIT: large white connector to emissions computer
Small white connector to ?
Small green connector is hanging unplugged in my rig also.

 

[ToyotaMatt]

Regarding the two unplugged harness connections in your pic:

On my 2/76 the larger one connects to the emissions computer, which would be mounted to that silver colored bolt right above it in your pic. Not sure about the smaller one.

theirs actually 3 unplugged connectors if u look close a green in far ground and the white in middle


take note the black wire w / yellow stripe in white middle connector , thats

part of the KEY ON ign. circuit directly inline with the fuel cut and others


@bhsdriller , now got to your starter , remove the smaller black wire w/ yellow stripe connected to your starter solenoid via . a
.250 / 6.3mm femail spade connector .

may have been repaired and look different but should be only 2 wires on

starter , BIG battery cable and small solenoid wire , LEAVE battery cable alone

pull off female spade , wrap in ELEC. tape so as NOT to earth ground it by accident

DO NOT SKIP THIS tape starter wire temporally off or cap off step please .....


engage ignition switch so as to blow a fuse again in the Key ON position


report back your results ,

hook up ign. swicth green connector too dont forget prior to this test ..


lets take a lookie lookie see at the starter selonoide circut and see whats what there

 

[ToyotaMatt]

Look at the tip of my Pencil , this is the female spade IGN. connector to remove

then tape off temporarily ,

 

[Dizzy]

The voltage regulator has a wire running to it from the engine slot in the fuse block.

I don't think that the starter is fused, aside from the fusible link at the battery, running thru the ammeter, but not the fuse block.

If you are having fuses blow, disconnect the battery and test the circuit for conductivity to the engine, frame, or body before you install the battery or fuse, otherwise you are making tiny sparks exceeding 15amps at the ignition switch.

 

[bhsdriller]

Starter wiring looks good.
One thing I forgot to mention earlier is that with no 15a engine fuse I can jumoer the idle solenoid to 12v and it starts/runs fine.
Everything works

 

[Solace in Solitude]

Make sure the black with yellow stripe, 10ga wire insulation isn’t melted in this enlargement of your picture

 

[ToyotaMatt]

Make sure the black with yellow stripe, 10ga wire insulation isn’t melted in this enlargement of your picture

View attachment 2165955

Keen Eye Danny !

 

[ToyotaMatt]

Starter wiring looks good.
One thing I forgot to mention earlier is that with no 15a engine fuse I can jumoer the idle solenoid to 12v and it starts/runs fine.
Everything works


View attachment 2165720

So what you are saying is the Solenoid IS indeed part of the troubled 15A issues circuit

or

Not ?

also ,

Have You Properly Bench Tested you Ignition Key switch yet

by the FSM Book chassis body , step by step as its written ?