My brother was changing his alternator belt, last night and had a dumbass moment and forgot to disconnect the negative wire and subsequently crossed the wires. He has no power and the car won't start at all, he has checked and changed all of the fuses. He has also swapped out ECU's and still no luck. Any other suggestions?

 

Start with checking the condition of the battery. After you verify that the battery is still in working condition you need to check for voltage on the two Black wires at the engine fuse box for everything electrical starts from there except for the starter itself but the starter cannot be turned over w/o power being fed to and through the two Black wires mentioned.

 

He has 12v coming from the main fuse wires, he only has 2v going to the starter and no power at all going to the fuse box on the kick panel. My father and I are helping diagnose this from 500 miles away as well.

 

Explain NO POWER please.

Usually there will be power for the headlights which are not dependent in any way on the ignition switch. Meaning I want to know if the headlights work or not. If they do, then that means the engine bay fuse box is getting power from the battery.

Next. Let it be known that the interior fuse box gets its power from the IGNITION SWTICH via a single black wire from the engine bay fuse box. The exception to this is what is called the BATTERY BUSS in the interior fuse box which consists of the top two rows of fuses. Those fuses are things like the room fuse, stop fuse,hazards and illumination fuses. IF the interior lights work, then the interior fuse box is being fed batt power from the engine bay fuse box. Have him step on the brakes and see if the stop lights come on to prove that row of fuses have power or not. Or if the interior lights work that would prove the BATT buss is good in the interior fuse box. Or honk the horn to prove the interior fuse box is getting pwr to the batt buss.

To see if the igniton switch is passing power to the interior fuse box to power the IG1 row of fuses which are essential for starting the car, have him put the key to ON and select right or left turn signals. IF they work then that row of fuses have power to start the engine. IF not, then the problem lies with the igniton switch not sending power to the interor fuse box when the key is put to ON.

IF putting the key to ON does not power the interior fuse box find out why the BLACK wire in the igniton switch plugs is not getting power from the engine bay fuse box. The MAIN fuse has to be good for that to happen. I assumed it was checked as good. So go to the engine bay fuse box and look approx six inches below and inboard of that fuse box for a single black wire with a single connector. That connector if disconnected will cause the ignition switch to not have power.

I also assume the battery is connected up right and not backwards. ha.

The starter gets batt voltage directly from the positive post of the battery FYI. I fail to see how it could not have power. Unless you meant the small trigger wire on the starter solenoid which won't have power if the ignition switch is not getting power from the single BLACK wire that feeds the igniton switch.

Look carefully at the interior fuse box shown in the jpg. Look at the bottom of each row of fuses. On the top two rows you'll see( B) below the row indicating that row has power 24/7 from the engine bay fuse box. Then look at the next row called (IG1) which gets fed from the igniton switch if the key is to ON or better. Then IG2 below that row which gets fed power if the key is to ON but not when the key is to Start.

IG1 row of fuses is essential for starting the car. I still do not know what NO POWER means exactly. Give a list of anything that works.

Sure the batt is not connected up backwards?

 

There are two wires that lead to the starter which have power. One is a large gauge wire that comes directly from the positive battery terminal and should have battery voltage when not starting, and then it would drop when starting the car. I'm assuming you are referring to this wire and not the one connected to the starter solenoid. If that wire only has two volts to it then something is wrong with the battery for the wire is a straight shot from the battery to the starter.

The interior fuse box gets its power from the ignition switch when the key is turned to acc or on and "directly" by the "Black" wire that comes from the engine fuse box. There is a connection of the engine harness and front harness which connects the Black wire to another Black wire so it could make its way through the firewall and this connection is located between the engine fuse box and the battery. Both sides needs to have battery voltage for the ignition switch and a couple of interior fuses to receive power. Fuse box also receives a White/Red wire from the engine fuse box which "should" allow the horn, headlight, tail lights, sidemarkers and front parking lights to turn on. If the Red wire at the engine fuse box has power it then powers the headlight relay and headlight switch to turn the headlights on and the White/Green wire at the engine fuse box allows the headlights to pop up and turn on the other lights mentioned. Do these lights at least work? If the tails and sidemarkers and flashers don't work then the White/Green wire is not connected properly to the interior fuse box anymore.

Lastly, was the "main" engine fuse replaced as well? This fuse is screwed into place and doesn't just pop out like the others. If it is damaged then the ignition switch among the other things connected to the Black wire will not have power.

 

No power means no power no nothing, no lights, no horn, not a darn thing. The battery was never the issue it was a simple mistake of trying to cut corners and not disconnecting the negative terminal. Yes it is a good main fuse and is brand new. I wish I could say something would turn on but from what he is telling us nothing is turning on, there is no power making it to the interior fuse box nor to the starter. This is a challenge because like I said we are trying to help diagnose from 500 miles away, we have even opened my 7's hood to see if we could get an idea of what he is looking at, the biggest difference is mine is an NA and his is a turbo.

 

Have him remove the four wire plug from the main relay and check for battery voltage on the Black/Green wire and White/Blue wire. No key necessary since this is constant voltage. If there is no power then either there is no voltage coming out of the engine fuse box on these two wires or the wires are frayed to the point where they are not able to carry voltage.

The Red wire coming from the fuse box goes to the headlight relay and the plug has four wires which two of them are Red and carrying constant voltage. Again, if these wires have no voltage at the relay then the wiring became overly frayed, the connection at the fuse box is poor, the fuse box is damaged, or the fuse box is actually not receiving power but he says it is and that the wires coming from the engine fuse box have power.

Is the negative terminal of the battery grounded? Grounds first at the inner part of the fender beyond the engine fuse box as well as at the starter itself. These need to be checked as well as the voltage of the battery.

The condition of the battery before is not an issue. Now it is. We're talking electrical trouble and it needs to be addressed.

 

Can your brother log on here himself?

3rd party trouble shooting is always problematic.........................

 

Very good point and if he needs to log on under the brother's name then so be it.

 

No headlights and no nothing means to me you need to take a digital meter and go to the engine bay fuse box.

The batterys positive post has two cables attached to it. One is large and feeds the starter power. The other cable goes to the front of the engine bay fuse box and is held on with a 10mm size bolt to feed power to the engine bay fuse box. See if power exists on that bolt. Probably does since in one of you first posts you say the MAIN FUSE has power.

At this point we have a problem. IF the MAIN FUSE has power, then the HEADLIGHT fuse, RETRACT fuse and BTN fuses have power. It comes with the territory that it has to be so. There fore the headlights should work when the headlight switch is put to ON. The headlight switch does not have to have power for this to happen 'cause all that switch does is put a ground on the headlight relay up fron which in turn is fed batt power from the afore mentioed HEADLIGHT FUSE in the engine bay.

So I have no idea why he has NO power to anything at all. I can't fix it and that's a fact. If power goes to the MAIN FUSE then the other fuses in the engine bay HAVE TO HAVE power also.

The interior fuse boxes BATTERY buss is fed from the engine bay fuse boxes BTN fuse if memory serves. Make sure the BTN fuse is good. Also pull the BTN fuse out and with a meter probe where the front tang of that fuse mated in the engine bay fuse box. Should have batt power from the batterys positive post (remember the small cable on that post feeds the engine bay fuse box as I mentioned). The BTN is the 60a fuse in the engine bay.

Send the car to me via UPS and I'll fix it for cost. You pay shipping both ways.

Could be the batt cables are not attached good or have heavy corrosion and are only passing on very little current or the small cable that sends power from the batt positive post to the engine bya fuse box has a loose connection at the front of the fuse box.

ECU's have nothing in this world to do with feeding power to headlights.......interior lights......horns.........turnsignals .....hazards.............stop lights etc. Wated time and money changing ECU's out.

No power to the starters large cable and no power to anything else indicates a bad cable attachment on the battery or a bad battery.