You have a ground/short on that circuit, do not use a higher amp fuse, you will melt the wires..

Make a jumper and insert a fuse and lamp into the circuit, then trace the wires with either a DVOM or a tone generator...

Check the heater circuit to the O2 sensors, they are known to burn against hot exhaust...

.... Philip

 

First, x2,3,4 to Aqua's advice about never using a higher rated fuse. The F1 fuse is 15amp, and that's all you should try. Sadly, the circuit that runs off that blue/black wire is quite extensive. Some people are quite lucky, and immediately find that the o2 wiring is hitting the hood, for example, shorting out the circuit. Another common short area is the fuel pump. Otherwise, it is a bit of a search, however, on the bright side, at least your short is not intermittent.
Fortunately, each of the components on this circuit has a connector - you can unplug connectors to try to find which one, when plugged in, causes the short. Or try with an ammeter. Your basic problem will lie with either the ECU, distributor, solenoids/relays or fuel pump circuit - somewhere, some wire is shorting to ground.
If you have a box of fuses, put your 15 amp fuse in, and pull, for example, the fuel pump relay - does the fuse blow? If yes, another fuse, then try each of your solenoid/relays on the circuit, saving the ECU until last. Remember that each of the connectors has a locking tab that must be depressed to disconnect them. Go through each of your circuits.

 

Rather than just blowing fuses, the bulb/fuse in series will allow current flow to circuit without losing fuse. The removal of the ground (load) will display in the brightness of the bulb...

..... Philip

 

Ah, yeah - If you remove the fuse, and use a test light in its place, the light will be bright because there is a short somewhere on the fuse circuit. Then disconnect components, one by one, until the light dims or goes out. Then you have found the bad circuit.

 

the car ran with 30a fuse instead of 15a, but now also blows 30a immediately when i switch the key to on position.

ive unplugged all connections behind the left rear taillight but cant seem to find any ground connections there. fuse blows with everything unplugged

You don't say what kind of condition your truck is in or how many miles
Rust is a problem on these trucks as the age and the wires rub away insulation from the wires, including on top of the fuel tank.

If your problem is in the wiring harness then unplugging components is not likely to help unless you move the shorted part away from a metal surface. Tho you may be able to isolate the problem to a certain part of the harness.

 

If your problem is in the wiring harness then unplugging components is not likely to help unless you move the shorted part away from a metal surface.

If you unplug the component, you break the circuit, so it makes no difference then if a wire is shorted to a 'metal surface', unless that surface is powered.

 

I suspect that "diagram" is missing quite a few things - the H20A engine has six ignition coils, none of which are shown, and all of which, if I'm not mistaken are powered from that fuse.

 

Ah! yes, but the OP is opening up at the end of the circuit, after the short to ground...

He needs to be pro active and work toward the issue, that way he can isolate it..

.... Philip

Note: not sure the OP is interested,, no post since the first...

 

Exactly....

but we don't know if OP opened the circuit going to the fuel pump either.

 

Personally, I would connect the signal generator and run the loom (non invasive)..

.... Philip

 

thanks for all the replies. i'll be working on the car tonight and keep you posted.

does anyone have the actual diagram? its a 97 vitara.

a mechanic advised me to cut the wire from the fuel relay to the pump and lay a new one.... i think ill do that in the end but im more worried about all the other components that feed off of this fuse. very strange way to connect a fuel pump, mixed together with all kinds of shit.


edit: one more thing, do i have to worry about the main relay not making any sound when i turn the key on ? i also cant seem to get any reading from the ecu with a scan tool, probably because of the everblowing fuse

 

thanks for all the replies. i'll be working on the car tonight and keep you posted.

does anyone have the actual diagram? its a 97 vitara.

a mechanic advised me to cut the wire from the fuel relay to the pump and lay a new one.... i think ill do that in the end but im more worried about all the other components that feed off of this fuse. very strange way to connect a fuel pump, mixed together with all kinds of shit.

If the "mechanic" has not been hands on, caution before cutting/replacing wires to individual sections..
Trace out the circuit....

.... Philip

 

im actually kind of scared of cutting wires when im not 100% positive of having the right diagram.. will try the lightjumping first and then see what happens

 

Quote:
Originally Posted by Bex View Post
He is only disconnecting the fuel pump connector. The F1 fuse runs many more things than just this circuit - I would assume, if the fuse continues to blow with the connector disconnected at the left rear tail light, his short is elsewhere.

Remember this...

Quote:
Originally Posted by Bex View Post
I have learned never to presume here....

Actually Bex reported a logical conclusion to the information, she wrongly identified her findings as an assumption/presumption.

..... Philip

 

ive unplugged all connections behind the left rear taillight but cant seem to find any ground connections there. fuse blows with everything unplugged

Yup, actually no assumption here, considering the above info from the poster.....

 

I have explained this phenomena many times.

When there is not a GOOD electrical ground, (not mechanical), any high draw will find its way via any other circuit.

So, an engine start with a bad electrical ground (bonding cable) can draw up to and greater than 400amps... frying/melting such mechanical grounds as shift cables, accelerator cables, clutch cables.. and any other wire/component connected to ground..

.... Philip

 

It is called The path of least resistance. Which is exactly what happens when insulation is rubbed of of wires and the bare wire contacts "ground".

If ground is powered (by some phenomenon) then the current draw would be less.

 

Ed, no need to explain to me what is being said. My point is that this circuit encompasses other solenoids, sensors, etc., other than just the fuel pump connection behind the left rear tail light. The poster advises that the fuse continues to blow, even with the fuel pump circuit disconnected, which would indicate that the problem may not be on this part of the circuit. While it has been indicated in a post here that 'unplugging components is not likely to help', under normal conditions it will isolate the portion of the circuit that has the problem. Sadly it would appear that this post has gone beyond the perimeters of this forum, and has allowed some individuals to air issues that are best left to Dr. Phil. I apologize to the original poster.

 

Ed - the point of this is simple - Gumby chose to nit pick over the term "powered metal surface" claiming he doesn't know where to find one, suggesting it doesn't exist.

Whilst I agree that under normal circumstances, it should not exist, the fact that we are troubleshooting an electrical problem is an indication that this is not a normal circumstance - you have accurately identified one cause of a "powered metal surface", there are others, and they can cause repeated failure of a fuse.

I spend my days troubleshooting electrical issues, not always automotive related, and I've seen stuff that would make your hair, literally stand on end, and I don't feel I've seen it all.

Simply put, and I believe this is the second time I am saying this - or words to this effect, hence my previous comment on deja vu - one should not assume that because you have no experience with a particular scenario, that it cannot occur - do not put down another poster because you feel the scenario they put forward cannot exist - these for a are made richer by the sharing of the collective experience.

If you want I can point you to another Trackick forum, a "one guru" forum, and you can see how you feel about not having the interaction of your peers.

 

Therein lies the problem Ed - the moderators are tasked with keeping the peace, and I tired of the sniping very rapidly - if you check you'll find it primarily occurs with a very few individuals, who apparently have little respect for some of the other regulars.

One way to deal with it is to suspend and/or ban the offenders, which I avoid unless the less aggressive steps have been tried & failed - I will frequently edit personal attacks, but some of our regulars have made an art of putting, so to speak, no more than a toe over the line, making it a difficult call - they prefer instead to play with words and attempt to belittle the knowledge & experience of other users, and in so doing, reveal their own short comings.

 

If you want I can point you to another Trackick forum, a "one guru" forum,

Are you implying that you know where "Jerry" is hiding?

..... Philip

 

:amen: to DAT!

 

thanks everybody for your help. i ended up cutting wire from the fuel relay and laying a new one through the car to the fuel pump and problem is gone !

 

Glad you got it sorted...
and Thanks for your update.

Gumby...