C3 Turn signal short?!

OK gang this is Ken's puzzle for this month is.........

I keep blowing turn signal fuses. Let me tell you what I've done and found (or not found) so far. I'll replace the fuse (with the engine off) and the turn signals will function as intended. I start the car and the turn signals work just fine for several miles, but (it seems) that when I turn the ignition off something causes the fuse to blow. When I again start the engine turn signals are gone and the fuse is now blown, again.

I can find no damaged or grounded wire, as a matter of fact I have replaced several older poor splices that some bubba had done just in case.

I can find no super heated or melted wires.

Part of my confusion comes from the fact that they will initially work after fuse replacement and being driven then malfunction and blow the fuse.

Any ideas guys?

Have u tried a higher amp fuse??

In some cases, maybe like yours, 'Bubba' may have installed the wrong amped fuse. If things work fine with no 'load' (engine running only), and things start to go haywire when u actually drive, then additional loading of the fuse could be taking place. You might have to bump up from a 5 amp to a 10 amp for example. Let others chime in and see if they agree with my humble assessment before you try changing fuses Ken. Gotta protect Goldie first...opinions and/or technical advice/suggestions like mine need to be colaborated! :hehehe:

Just my 2 cents...

Thanks my friend. I am running the perscribed 20amp fuses but something is f*ckin goofy here.

If I remember correctly the directional lights share their fuse with the back up lamps so you may want to check the backup light switch and the lamps themselves. There might be a short there that isn't related to the directional lamps that's causing the fuse to blow. Might even want to try disconnecting the wire to the backup lamp switch and see if it does anything, but your right this is a very odd problem, hope you figure it out.

The only other thing I can think of is something rubbing inside the steering column when the key switch is turned off, doesn't make sense but seems to be the source of the short, or at least when the short occurs. of course this only applies if your key switch is in the column and not the dash

Thanks Palmbeachvette76. With the help of your advise and some direction from the national C3 forum I did exactly as you said. I unplugged the connector, replaced the fuse and everything works just as the factory intended (except, of course, the back up lights). Now I just need to figure out if it's the switch or something else in that circuit and remedy that.

Thanks,

Ken:thumbsup:

Right on brother, glad it worked out, well at least narrowed things down and who needs those pesky backup lights anyway

Hey Ken!

If u haven't tried here...

http://www.c3vr.com

go to that website, of which I'm a life member. Its a dedicated C3 site and they have answered just about every question I've had to post in the past.

Good bunch of guys. Just post your questions in the appropiate arena, as in "C3 Electrical", and I'd betcha you could get your answer! :thumbsup:

Since we were over I have become a part of the C3 Regrestry too but even another great source is Corvette Forum. It, too is nationwide and has some deep experience bases.


Now I just need a simple way to figure out if it's the wiring going to the back up lights, the switch itself or the receptacles.

Thanks Jack.

Ken

To track down the switch or wiring you'll need either a test light or a multimeter. If you have a multimeter you can use the ohm setting and put one lead on each wire from the switch and see if it works or not. One way it should show no reading on the meter and when you switch the switch you should get continuety.

Another simple thing would be pulling the rear lamps and inspect the bulbs for starters then remove the bulbs and use your test light or meter to check for power when the switch is engaged.

I never asked, but is your car an auto or manual trans

Alrighty here. It's a manual 4 speed but pls realize that ohms are what my dope smoking buddy in college 40 years ago used to talk about.

Ya gotta get far more step by step and detailed before my (I'd rather look at a cute figure) then figure out an ohms brain will understand. I do have an ohm meter but really don't know how to have it tell me anything that would roughly translate to english.

I do so appreciate the help. believe me.

Do I need to reconnect the back up light connector to test as you've suggested above? Bulbs look good and I don't see any real corrision in the sockets them selves, nor at this point do I see any fried wires.

Sorry about the techno jargin but ohms are easy, it's how you measure resistance in a wire, call it traffic report on the interstate -parking lot (resistance) or smooth sailing (no resistance).

Leave the connector disconnected from the switch. The switch is what I want to figure out if it's working or is creating a short to ground that is blowing the fuse. Chances are it's the switch but given the $72 price tag at Ecklers I would want to confirm it before buying one.

An easier way to test without a meter is to make a jumper wire and bypass the switch, trick the lights into thinking your in reverse when your not. If you have a piece of wire a foot in lenth or a little less would be fine. If you don't have it go to a local parts store, walmart, ace hardware, home depot, etc. and pick up one of the soldier less connector kits with a crimping tool if you don't already have one. These kits have different type and size connectors with at least one fitting for this test. They are normally a hanging item with red, blue and yellow connectors in a plastic see thru package.

I don't have a 4 speed switch in front of me so I can't tell if the wiring harness end that connects to the switch has a female or male end, I'm gonna guess female so you would want to use the flat spade looking crimp ends either blue or red depending on the gage of wire your using, if the harness end is male then use female connectors. Put a connector on each end of your wire then put the connectors in the wiring harness end. The wire will be a loop now.

All you've done is connect the 12v power wire in the harness to the wire next to it simulating what the back up switch does. If the lights come on and you don't blow a fuse then you know the backup switch is the source of the blown fuses. If the fuse blows then atleast you've narrowed it down to the wiring to the rear, the sockets or bulbs.

Let me know how it turns out and I'll be glad to help out in any other way I can. Good Luck :thumbsup:

Now I'm off to take the boat out on that big lake they call Atlantic and head up to Peanut Island with my wife.

I carry a blackberry so I get email notifications if you run into a problem I'm not totally out of pocket.

This is where I've made it too. I can (and did) use a jumper between the green and pink going to the back of the car. Vehicle started, turn signals worked and backup lights came on. The fuse never blew. I haven't got under the car to trace wires to see if anything is grounded between the connector and the switch as yet. But I'm kinda leaning toward the switch or a grounded wire at this point.

Kap142 said:

This is where I've made it too. I can (and did) use a jumper between the green and pink going to the back of the car. Vehicle started, turn signals worked and backup lights came on. The fuse never blew. I haven't got under the car to trace wires to see if anything is grounded between the connector and the switch as yet. But I'm kinda leaning toward the switch or a grounded wire at this point.

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That's good news you've narrowed it down to the switch area. If the wiring looks good I'd say the switch is the problem and your multimeter would be the only way to confirm it but it seems you've eliminated anything else. Good work :thumbsup:

Thanks for all the help.