Ignition Problem. Help!

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Ignition Problem. Help!

June 18, 2009, 06:07:26 PM

So today I went out to the Sport and tried to crank it, I got nothing. No radio, no lights, no anything! Their was a fusable link burnt under the hood near the starter relay. I replaced that. Its the link that goes to the negative battery cable. When I replaced it I tried again, still nothing. Would this fusable link going bad cause my ignition switch to burn? I havent checked it yet but I think thats my problem. Not the lock cylinder, I know they are both diffferent.

Ignition Problem. Help!

Reply #1 – June 18, 2009, 06:20:27 PM

Is the switch between a 4cyl mustang and 5.0 thunderbird the same? They look the same but I was wondering if they cary a different load or something?

Ignition Problem. Help!

Reply #2 – June 18, 2009, 07:21:09 PM

quote from ThunderChicken:

The new switches are identical to the old ones. The only difference would be the part number stamped on the switch - the original switch would have a part number that starts with "E", while the new one would have a part number that starts with "F".

You won't see any exterior signs of problems unless the switch has actually burned (I had one burn a hole right through the side). The problem with the switches is in the contacts (plates) inside the switch. They wear over time and the copper filings that wear off them builds up between the plates, causing shorts. At the same time the wearing plates make poor contact with the slider (the thing that moves when you turn the switch on), and poor contact causes heat.

Regardless whether your current switch is an E (old) or F (new), if you're having symptoms of a bad switch, replace it. Don't cheap out with a used one, get a new one.

As for what problems to look for when a switch fails, you've already experienced one of the early symptoms. Another common symptom is an engine that starts but the heater, gauges and turn signals don't work. Basically, any time you have multiple systems fail at the same time (such as heater, turn signals and gauges) it's usually the switch.

There is nothing you can do to prevent the problem altogether, aside from rewiring the "power distribution" circuits that feed the accessories in the car (which I have done in my car, but it is not a job for a novice). A new switch still has the inherent flaw, but it should still last many years before failing again.

My car: I have pulled the switch. My switch is stamped "F".

Ignition Problem. Help!

Reply #3 – June 18, 2009, 10:23:25 PM

This is a dumb question, but did you make sure the battery isn't dead? I know you found a burned link, but who knows how long it was drawing before it burned.

CoogarXR

Ignition Problem. Help!

Reply #4 – June 18, 2009, 10:29:06 PM

The new switches just "look" identical to the original, they have wider contact spacing so are "improved" but not fool proof...

I guess I've been lucky, out of 13 TCs, 4 5.0 Birds and a 2.3 & 5.0 Stang, I've never had a issue... I did have a original switch that was bad in a '88 Aerostar(same one that's in the Birds)... It'd just quit occasionally while riding along, but I could never make it act up... Always did it when I was in heavy traffic, so I couldn't diagnose the problem(just restarted and went on)... Finally it quit one day setting at a light, and it was dead, no warning lights, nothing... Jiggled the tumbler and it came back to life, restarted it, came home and changed the switch...

Ignition Problem. Help!

Reply #5 – June 18, 2009, 10:40:14 PM

Quote from: CoogarXR;278584

This is a dumb question, but did you make sure the battery isn't dead? I know you found a burned link, but who knows how long it was drawing before it burned.

CoogarXR

That my friend is not a dumb question because it was indeed DEAD! lol

Im glad we checked before I pulled anything else apart. I just pulled the plastics off the column to inspect the switch. I did buy a new one just in case while I was buying a new battery. My old battery had a dead cell and wouldnt take a charge. So there is my "blonde moment" of the week! :D

I guess that burnt fuse was the cause of the dead battery??

Ignition Problem. Help!

Reply #6 – June 19, 2009, 12:31:34 PM

At least it was simple. I've had Fords for many many years. I've had to replace the ignition switch in every single one of them. Same thing. Everything was dead.

The last one I replaced was on my wife's 92 Bird because the starter was bad. Simptoms of a bad switch that I experienced in the past.

Now I have a spare.:D

Ignition Problem. Help!

Reply #7 – June 19, 2009, 01:33:11 PM

I have had a few switch's go bad and when they did I had no power to anything so I assumed that was the case again.