Bypassing ignition switch - wiring problem prevents start

Certainly. I just drove home in a Volvo 245 with this exact workaround, done for your exact reason. There are two "wires" attached to the starter: A small one and a large one (cable). All you need to do is run a wire from

+12V to your pushbutton switch, and from your pushbutton switch to the small terminal on the starter.

Without the ignition key in the "on" position, pushing the start button will cause the starter to crank the engine, but it won't start.

DS

Why not just get your +12V from the "acc" or "run" terminals? that would solve that problem...

nate

Chris wrote in rec.autos.tech

I have 3 alternative suggestions myself. But first, I want to say something here, that I think you and your friend need to take note of. I used to be an electrician, and I know that insulation on wires do not just melt. I worked in a plant where we had temps in areas that would reach several hundred degrees. Yes we melted wires, but not one wire in a run. And never melted wires, unless they shorted, as long as the wires were away from the heat. It takes some fairly high temps to melt that insulation. Of course, those temps are reached if something happens to the wire and it shorts to ground. Or, what it is driving is drawing too high of current, or the insulation is rated wrong. The thing that really gets me is that apparently no other wire is getting hot and melting, even though they all run together in the column. If the Texas heat were that bad, all the wires would be melting, not just one that gets intermittant use. It is possible that the wire is rubbing in the steering column, or where it comes out, or somewhere along the way to the solenoid. Or it might be running too close to something hot, such as the exhaust, or the solenoid has a real problem.

Murphy suggested running a wire from the battery to a switch and then to the starter, I don't recommend this because you then lose any protection you might have had. First of all get a shop manual that includes instructions on accessing the igntion switch and wiring diagrams for your car. You could get the info by going to your local library if it has a subscription to All Data and getting the information from them. Or subscribing yourself, or your friend at

First suggestion: Locate the bad wire as it comes out of the steering column, along with the wire that is hot when the switch is in the run position. Make sure that the wire is good at this point, follow it all the way to the solenoid or relay it is going to. If it is going to a relay, follow the wires from the relay to the starter solenoid. Make sure that the wires are intact all the way through. This is neccessary as you are going to use the wire for your starter button. The wire that is hot while in run should be found at the fuse block, if you are lucky you will find an empty fuse holder that it powers, if not, use an inline fuse. 5 or 10 amp should be more than enough. Now connect a pushbutton between those 2 wires. Thus you will have a starter button that will only work when the car is turned on, and will be protected by a fuse in case of problem. Next suggestion: Check the wire inside the steering column, if it is truly melted, then go to a hardware store, or an auto parts store, and find some wire of the appropriate size, and a good temperature rating, and run this wire through from the switch to the solenoid or relay.

And now for my third and final suggestion: Ask a dealer if there are any Technical Service Bulletins on this problem. Looking at all data, there is one titled Instrument Harness - Chafing at Steering Reinforcement Seems like that could be part of the problem.

Should work just fine. That's actually the solution I was thinking about as I read your problem. Remember you should be able to test your fix before you make it permanent with temporary wires or clip leads.

What you want to do is supply +12 volts to the starter solenoid whenever you press this momentary switch.

GK

Thank you so much to everyone for your replies. I'm glad to hear my idea wasn't totally off the wall, and is actually in use by others for the same problem :)

Dick C - thanks for the detailed info. I agree that the supposed 'Texas heat' problem sounds rather off the wall, and it is very suspicious that only the starter wire goes bad every time, while every other wire remains fine. But, I do know the starter works, and I figured by doing a 'home run' with wiring straight to the starter I would bypass whatever the problem was, wherever it was. I'd suspect some kind of steering column chafing or other mechanical issue/loose contacts/whatever before I'd suspect heat or anything else ... but as long as I'm running the wire and keeping it nice & tight & clear from everything else I'm sure it should be fine. And yes, I was already planning on incorporating an inline fuse into my circuit just in case (and of course it's just going to be a simple momentary pushbutton that only gets used briefly to start the car anyway).

I'll try to get a Chilton's or Haynes from the library (or look into alldata - thanks for that link, I hadn't known about that before) to make sure I've got all the wiring right and give it a try as soon as I get a chance, then I'll let you know how it worked out!

Chris wrote in rec.autos.tech

You are very welcome. This fix is done every once in awhile. Usually because the start portion of the ignition switch is bad, and they can be a pain to replace, especially if you want to keep the original key.

Just a quick followup - it's working fine (just did a simple check with test leads) and now all that's left is trying to route the damn wires through the firewall etc. But it's gonna work!

I was worried for a minute because I did some checking with the multimiter, and the problem is actually NOT in the steering column as the shop said (or at least it's not this time) ... I was getting +12V all the way past the clutch switch when the ignition was in the 'ON' position. As soon as I discovered that, I started worrying that the starter or solenoid had gone bad ... but it turned over just fine when manually running 12V to the solenoid. So the problem appears to be somewhere between the clutch switch and the starter. But since this has been such a chronic problem (and apparently might be occuring in more than one place) I'd rather just run a whole new wire anyway.

So now it's just a quick trip to get an inline fuse holder & switch, and then crawling around in cramped spaces trying to find a good place to run it :) Some days I wish cars were about 10 times bigger so there'd be some room to work

Chris wrote in rec.autos.tech

It sounds to me like the shop lied to you, surprise! It sounds like you will find that the wire going to the solenoid has melted somewhere around the exhaust manifold. Make sure you do not route the wire close to the manifold, and use a wire with a decently good insulation.