Sunday, May 18, 2008

First work on the S10; bed removal, keep the wiring harness?

I got to work on the S10 Saturday afternoon, after doing some errands and chores. I only got about 4 hours in, but I made some progress. The main thing I got done is removing the bed. It isn't that difficult, but taking it off makes such a difference visually that it looks like I got a lot done in a short time. A few friends (thanks guys) helped me physically pick it up and take it off on Sunday. The bed is surprisingly light; I would estimate no more than 250 lbs. I expected it to weigh about 500. Interesting.

I do as little work under stock vehicles as possible. Mainly because it is inevitable that I will get at least a little grit in my eyes, and my contact lenses are very unforgiving in terms of comfort if I get even a small bit of grit in them. Glasses don't give me great vision, and goggles are uncomfortable, fog up, and grit gets around them anyway.

The work I was doing required that I get underneath, and of course I got some grit in my eyes, so it was not great fun after that. I was spurred on by the fun of disassembling the truck though. I also got some of the wiring harness disconnected. I am planning on using it to rewire the F100, so I have been diligently marking EVERY connection I undo with marker on a masking tape label.
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By the time I got into the underhood area, I began to realize how complicated the stock wiring harness really is. Hoo boy. There are A LOT of sensors. There are airbag sensors (and airbags inside. I don't know how I'm going to get them disconnected yet). The truck has ABS. The brake combination valve is ganged onto a huge complicated valve body of some sort that has like 3 wiring harness connections going to it. I assume I will have to substitute a non-ABS combination valve later, since I am not going to use ABS. All that mumbo-jumbo just because people don't know how to stop a vehicle. Unbelievable. There is an underhood computer with more connections.
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I was able to do a bit more on Sunday. More wiring harness labelling and disconnecting. I want to reuse this harness, but what a job this will be. I now expect that I will have to trace a lot of wires and make "jumpers" to complete circuits that have sensors that I am not using. I could just clip off unused connectors, but I doubt I could be satisfied with ghost wires (wires that lead nowhere) left in the harness, so I would end up taking the harness apart and rebundling it at some point anyway.
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I began taking the dash apart, but did not get too far. I keep looking at the airbag in the steering wheel, expecting it to blow open at any second and hit me in the head, snapping my neck and killing me. Not good. I don't know if this could happen without power, as I have the battery out. But maybe there's a capacitor in there storing energy in case of battery loss, I don't know. Don't want to find out.
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I have done a couple of complete wiring jobs on race cars, even using relays for higher load circuits and such. I think I could do this vehicle as well, but wiring a car from scratch takes a long time too. I look at time spent on this project in terms of real world labor cost and opportunity cost. A new wiring harness kit for the F100 is about $300. Professional auto repair rates are close to $100/hour. A pro shop would likely start with a kit anyway and the labor would be tacked on from there. So if I get the kit and install it I'm saving $100/hr.
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How much could I earn at my job in an hour? It's no $100, but it's something. How long will I have to mess with the S10 harness to get it to be useable? 10 hours? 20? Time is precious to me now. That's the opportunity cost; the cost of what I can't do during the time I'm working on the project. My point is this: it looks like reusing the stock S10 harness might take more time and effort (and $ value) than getting a new harness kit. I'm cheap, $300 is as much to me as it is to the next guy. But why rebuild junk to save a buck? The problem with doing so is that at the end you just have rebuilt junk that you wasted a lot of time on. I'll keep working on the stock harness for now and see how it goes. A lot to think about though.

2 comments:

Unknown said...

To explode or not to explode - that is the question. Concerning your airbag accidentally going off concern, I wouldn't really worry about a capacitor. Suppose for a moment that car companies did indeed install a capacitors in the event of loss of power in a collision. Said capacitor would only need to store power for a few brief moments. But let's say that they stored power for 5 minutes (which, would be at a very far maximum). There would really be no need to store power for more than that, as I don't know if in the history of the world there has been an accident that has lasted for longer than that. And if an accident DID last longer than 5 minutes, I'm not sure an airbag would be very effective anyhow. So, having your battery disconnected for any length of time should take care of any capacitor concerns.

Now I don't know if all airbags work the same, but,

The sensor is the device that tells the bag to inflate. Inflation happens when there is a collision force equal to running into a brick wall at 10 to 15 miles per hour (16 to 24 km per hour). A mechanical switch is flipped when there is a mass shift that closes an electrical contact, telling the sensors that a crash has occurred. The sensors receive information from an accelerometer built into a microchip.

If what triggers the inflation is an electrical contact during a mass shift, although you may have a mass shift when taking them off, any electrical contact causing a closed circuit would not be effective since there is no current present.

But then again, if something happens, can I have some of your tools?

John Kosakowski said...

A very logical and well thought out comment. Thank you. Your knowledge of airbag sensors is, well, unbelievable. Who knows this? I didn't know this. I feel better now. I guess you're right, otherwise airbags would be sitting out there like unexploded mines, going off in car crushers and such.

You have indeed earned first pick of tools. Well done.