94 Wiring Problems (no Power)

[big steve33]

I bought this 94 a couple months ago. It was a stolen recovery and all the harness under the hood was cut apart when the motor was pulled out. I have replaced the harness but have no power. Where does the fuse box under the hood get power from? Do I need to run a jumper from the battery to the stud on the fuse box?

 

[revhead347]

Yes. The positive battery cable splits on an SN. Once cable goes to the stud on the fuse box, and one cable goes directly to the starter. You are going to have to kind of make your own, because the factory cables are outrageous. I called the Ford dealer, and they wanted $740 for a stock set of battery cables.

Kurt

 

[toyman]

Actually making your own isn't a problem. Run a pre-made cable of the length needed from the battery to the fuse box and another cable from the fuse box to the starter. Cost probably under $25.

 

[big steve33]

Thanks. I already ran a cable from the battery to the starter. I just wasn't sure about the fuse box. I ran a wire from the battery to the stud on the fuse box and got everything working. It didn't fire off but I'll look into that in the next couple days. Can anyone tell me what the two black sensors are that are bolted right behind the grill?

 

[toyman]

If you mean in front of the grill probably the air bag sensors. Black boxes on either side of the running pony.

I ran a wire from the battery to the stud on the fuse box

I hope you mean a 2 ga. cable when you say wire.

 

[JCode95]

If you mean in front of the grill probably the air bag sensors. Black boxes on either side of the running pony.

I have been patiently waiting for a rock or other piece of debris to hit one while driving. Could have picked a better place.

 

[revhead347]

I don't think a rock would set them off. They are crude accelerometers, and a rock wouldn't cause a sudden deceleration in the sensor.

Kurt

 

[JCode95]

I thought it was impact that set them off. The more you know.

 

[toyman]

Rapid (severe) deceleration. Here's Fords description of how it works.

The air bag system is designed to :

l Operate in frontal or front-angled collisions.

l Activate the air bags in a crash with severe frontal deceleration, more severe than hitting a parked car of similar size and weight head-on at about 45 km/h (28 mph).

l Sense the severity of the crash rather than vehicle speed, thus some frontal collisions at speeds above 45 km/h (28 mph) may not be severe enough to require air bag inflation.

The sensors in the vehicle determine if air bag inflation is required in the following manner:

1. During severe frontal deceleration caused by an impact that decelerates the vehicle in the forward direction, both a radiator primary crash sensor and a safing sensor will activate.

2. When a primary and safing sensor are closed at the same time, electrical current will flow, igniting the driver side air bag module and passenger side air bag module.

The primary sensors measure the crash severity while the safing sensor confirms the crash and is used to prevent inadvertent deployments possibly caused by a malfunction in the primary crash sensor circuits or crash sensors.

 

[revhead347]

My understanding is that it is a ball sitting on a magnet. If the deceleration is quick enough, the ball will come off the magnet which completes the circuit.

Kurt