Fried Indicator Switch Advice Please

Steve · Post by **Steve** » Thu Dec 18, 14 6:39 pm

Men.... I have completely rewired the indicator system on my Fury and had an issue with my new switch yesterday. I think I know the answer but just wanted to run it all past you so I dont ruin another £80 switch!!!

Basically, I was having problems with broken original switch so ordered an exact repro. While waiting, I have rewired the system (retaining only the original feed). Ive made new bulb holders for the front indicators that are rubber mounted into the original housings. As they originally earthed through the metal to metal, holder to housing contact, I have incorporated earth leads from the new holders to a body earth. Rear reverse lamp holders have earth leads as well and Ive run new wiring from all four corners to the switch. The only original wires are from the switch to the dash warning lights and from the flasher relay to the switch.

After fitting, I started the engine and indicated left. All good. Indicated right and front pass lamp didnt work. The dash light was dim. I noticed that I hadnt attached the earth strap on the offending corner so the unit wasnt earthed. I checked the spade connector close to the indicator unit that connects the new holders into the new run of wire from the switch and it was hot. I immediately killed the ignition but it was too late. a small section of plastic in the switch had melted, knackering the switch.

My question is......does the fact that the earth was off account for this heat build up???

My head is saying YES but Im thinking that, as the front and rear units on the same side are in the same circuit through the switch, should the front one jump onto the rear earth?? Then Im thinking that if that was the case, you should be able to remove an original style holder and it would work (which it doesnt). Usually, a bad earth just means the indicator doesnt work, it doesnt burn the switch out or create heat (I dont think so anyway). To me, heat is a by product of resistance.....does no earth just stop the circuit working or can it also create resistance/ heat??

I really dont want to fry another one so want some thoughts on whether my earthing blooper can account for my issue please before I fit another one!

Cheers Steve

Blue · Post by **Blue** » Thu Dec 18, 14 6:46 pm

Sounds like you have a dead short, your "earth" is live for some reason.

Steve · Post by **Steve** » Thu Dec 18, 14 6:54 pm

Gotcha Blue.....so, if I do a continuity test from the end of the new wire by the switch too the end of the earth lead from the holder, it will beep if there is a crossover from the live side of the circuit to the earth side??

When I made the holders, I did a continuity test from the centre stud in the holder where the base of the bulb contacts and the end of the earth lead and there was no beep indicating no crossover. Would this test find that fault you are on about Blue??

Cheers Steve

Steve · Post by **Steve** » Thu Dec 18, 14 7:21 pm

Found this on google......

A dead short is a short circuit that creates no real resistance, allowing the amperage to build up until it trips the circuit breaker. These can be difficult to track down and diagnose because the current builds so rapidly that it usually trips the breaker immediately.
Dead shorts can be dangerous due to the high amount of current the situation creates. Repeatedly cycling the breaker to try to locate the short can cause damage to the wiring and present a major fire hazard.
Common causes of a dead short include a direct connection between the positive and negative power legs or a direct connection between the positive and ground wires without any load or resistance in between.

Got some testing to do I think....

If the connector that I mentioned prior to the holder had touched earth, would that do it Blue?? Its not sealed in heat shrink yet....

Blue · Post by **Blue** » Thu Dec 18, 14 7:23 pm

Electrics are not my strong point, I'm fine wiring stuff up but I struggle a bit when it comes to fault finding.

Pete · Post by **Pete** » Thu Dec 18, 14 7:29 pm

Sounds like you probably need to put a few in-line fuses in the circuits until you have tested and got it fully buttoned up...........

Steve · Post by **Steve** » Thu Dec 18, 14 7:33 pm

No probs Blue, you have pointed me in the right direction and I now know where to start looking. Thanks for your help as always mate.

I think Im going to test all the wiring again, insulate it all as I intend the finished system to be then test all four corners using a fused wire from the battery just to make sure it all works THEN fit the new switch...

Just one thing Blue, if I do a continuity test from one end of a wire to the other and part of it has grounded through bad insulation, will my meter still bleep??? I think it will so not a good way to find a short in a wire before I power it up....cheers

Steve · Post by **Steve** » Thu Dec 18, 14 7:35 pm

Sorry Pete, missed your reply whilst typing....thats a great idea! Even if I just put one in each feed from the switch out it will save my switch if anything goes wrong....cheers

Jon Connolly · Post by **Jon Connolly** » Thu Dec 18, 14 8:35 pm

Steve

I only executive read your post but I would look at the switch or anywhere you have " made off " terminal ends as it is very easy to have a strand of live or switched wire hanging out of a spade crimp or butt crimp and touching metal body.

This can also happen if the insulation over the crimp isn`t intact.

Jon Connolly · Post by **Jon Connolly** » Thu Dec 18, 14 8:46 pm

To test the switch switch off the ignition, pull all the connections off the switch. Put a meter set on OHMS on end on " common " and test the out puts with indicator in middle position you won`t have a circuit on either out put.

Put indicator to left position and test common to output 1 = should give a full reading

put indicator to right position and test common to output 2 = should give a full reading

If you get a partial reading on either side or no reading switch is Bananarama!

Steve · Post by **Steve** » Thu Dec 18, 14 9:09 pm

Thanks Jon....Im definately going to check all the wiring and insulation before I fit the new switch. Im a dab hand at testing the switches now, exactly the way you suggest. Thats how I worked out that the old one was duff and when I stripped it down, my diagnosis was spot on (makes a refreshing change for me!!). I even tested the new one before I put it in and all was good. I just wish I had paid more attention to checking earths, connections etc as its an expensive mistake!!

Thanks for your advice Jon

Cheers Steve

Mick · Post by **Mick** » Fri Dec 19, 14 4:59 pm

Could be a trapped or exposed wire, trace the wires through the cluster and check all your earths are intact.
I've just changed the indicator switch on my Duster, on close inspection it seemed fine but it was definitely faulty
Mick

Steve · Post by **Steve** » Fri Dec 19, 14 5:44 pm

Right then....sorted.....and Blue, you were spot on, thanks

Ive learned a good lesson from this, expensive, but good.

The problem was with the front passenger side indicator bulb holder that I made. The live wire from the seat of the bulb goes to the switch and the earth lead goes from the casing to the earth point on the body. I tested these wires for continuity and isolation from each other. All good so far.....my mistake was not fitting the spade connector to the power lead and the ring connector to the earth lead before testing. For some unknown reason, following testing, I attached the ring connector to the power lead and the spade to the earth lead. I wired it the wrong way round.

I corrected the wiring then made a long, fused, test lead. I clipped the lead to the positive side of the battery and the other to the power in side of the holder....worked perfectly. Checked all four this way and everything works fine. Problem solved I think.

The only thing that has me scratching my head is that I only had power going into the earth side of the holder and the other lead wasnt connected to the earth point. As it was loose I suppose the end could have been resting on an earth. If it wasnt, I cant work out why it all went wrong.....the only thing I can think is that the metal casing of the holder was touching the housing, causing an earth...ie power in then straight to earth through the casing.

Sorted anyway so onwards and upwards. Thanks for all the help

cheers Steve

Dave-R · Post by **Dave-R** » Fri Dec 19, 14 6:43 pm

Yes you would be getting a ground from the casing to the bodywork. Most Mopar lighting worked like that anyway. No earth wires on the turn signals.

Steve · Post by **Steve** » Fri Dec 19, 14 8:00 pm

Thanks Dave....Ive made new holders that are rubber mounted to waterproof them and dont have an intentional earth via the casing as per the originals. On closer examination, the metal bulbholder does just touch the casing but it doesnt rely on this for its earth. The earth wire from the casing to the body earths the holder. I can take the holders out and they still work. I never rely on the holder to casing as the earth as I learned the hard way on a dark run home in the Polara a couple of years ago!