HELP! I did the MAD electrics upgrade and then promptly set fire to the car..ish

[K9COP]

Hi Guys, thought I'd be proactive and do the 'MAD electrics' upgrade to bypass the AMP gauge and put the fusable links in, as my AMP meter had already burned out and was bypassed (both AMP meter terminals/cables moved to one post on the back of the AMP gauge). Please read through the the 'Problem' section below. long explanation, please stick with me.

While the dash was out, I wanted to examine why the fuel gauge wasn't working, and both rear turn signals flashing with the turn signal switch to one side. All other turn signals work correctly (Dash tell tale, front valance, hood repeater, problems that popped up since the steering box was swapped. See separate thread.

SO. I took the dash out, and found that one of the pins on the circuit board was loose so I very, very carefully soldered the pin back in and made sure it had a good fitting as per Lilwendels cluster restoration thread.. I then very carefully carried out the MAD upgrade. Black alternator wire off bulkhead connector and now to fusable link to starter relay, drilled red and black terminals out of both sides of bulkhead terminal block, soldered extensions to both wires under the dash, passed both through connector block, joined same with fusable link to same terminal on starter relay.

SO, with the dash out, car starts just fine, no issues. I put the dash back in, very carefully, and immediately upon start up:

PROBLEM:

There was an immediate short on one of the wires to the five pins on the back of the dash board circuit board. Melted wires, car filling with acrid smoke, scared shitless owner. Thank god for that battery disconnect I fitted!



The wire that burned is the brown, outer wire, on the right in the above picture. (Previewing this now, probably didn't need to explain which one was burned )



The burned wire goes on to the LEFT pin in the above picture (let's call it PIN #1 numbered left to right in that picture). Sadly, that's the one I soldered. The image is after my repair.

Upon examination, I found that there is continuity between the brown wire, and the wire immediately next to it IN THE LOOM/CONNECTOR.

I also found there is 14V on BOTH these wires in the loom (that go to PINS #1 and 2) . Is that correct? If so, looking at the board, it looks like PIN #1 feeds 12V to the bulbs, PIN #2 feeds voltage to the regulator, #3, #4, #5 feed signal to the fuel, temperature and oil pressure gauges respectively.

There is continuity between PIN #1 and the case of the cluster, and all around the track on the circuit board, as expected, including the case of the new voltage regulator. (should it be that 'sloppy' in the terminals?). There IS NOT continuity between PIN #1 and PIN #2 on the board.

Guys, where should I have voltage, and where should I have continuity please?

I'm guessing PIN #1 should be power as it joins the bulbs together. The other bulb 'terminals' appear to be earthed/grounded by joining up to the screws holding the board to the case.. Should that 'terminal' on the outside of the voltage regulator have a wire on it?

As I type this, I think I may have just solved it. If PIN #1 is 12V (14V), then it should not have continuity to the cluster casing, which is grounded, right?

Please pitch in guys. I'm guessing this is a me soldering a pin snafu. There's a reason they don't give cops anything hot.....

Yours, not filling out an insurance claim form,

CS

[A383Wing]

I say pin #1 is dash lights, pin #2 looks like 12v to instrument regulator, pin 3 looks like gas gauge sender wire, pin 4 looks like sender wire for gauge next to fuel gauge which I think is water temp. The screw for ground is for the dash light bulbs as well. Pin #1 should have 12v only when lights are turned on

Bryan

[K9COP]

Thanks Bryan. I think my dash lights are on all the time, hence PIN#1 is always live. See below, I think I cured the issue:

The problem was my soldering on the back of the board. This is a quote from 'lilwendal's excellent, excellent 'Cluster Restoration' sticky here: http://www.dodgecharger.com/forum/index.php/topic,37999.0.html

"Once cleaned and soldered you will be OK but you must add solder to the back side as well to help keep the pin with the board."

I added solder to the back of PIN #1, like this:



This is how it looks rested on the cluster housing:



Now, the rear of the pins fit into a register cast into the cluster housing. It"s not very deep though, as from the factory, it only has to clear the crimped ends of the pins on the back side of the circuit board. It looks like this:



Not very deep, is it? Now, if some ham fisted cop put a huge tower of solder on the reverse side of the pin to reinforce it, you see where this is going, right? The positively charged (14V) pin will touch the bottom of the 'channel' in the cluster housing behind the pins, and Robert's your Mum's sister!... = Car on fire.

SOLUTION:

a) PM lilwendal and ask him to put a caution in the sticky,

b) gently grind down (Dremmel) the surplus solder on the rear of the pin, to allow it to clear the 'channel' and not contact the cluster housing hence now not connecting 14V directly to earth/ground.

c) add a strip of insulating material to the 'channel' to be doubly/triply sure, like this:



Caution again!, the channel is not very deep, so I've replaced the white material in the picture with something thinner (and nicer cut..) to prevent any strain being put on the board as it is bolted down.

So now, NO continuity between PIN #1 and the cluster housing, and next job is to totally replace the burnt wire in the dash.

Hopefully I've had (another) lucky escape, and you guys can benefit from my experience.

CS

[charger Downunder]

Wow at least your car did not burn up. You have to always double check everything.

[Pete in NH]

Wow, what a statement of Murphy' Law- Anything that can go wrong will! Thanks for the detailed pictures and explanation. I'm sure they will help others in the future avoid the same problem. Sorry you had to find the issue they way you did and I hope the wiring repair work goes well. One thing I do when making wiring changes is to use an ohmmeter as a continuity checker and check for short circuits to ground on any power leads. because you never know when Murphy's Law might show up.

[K9COP]

OK guys, so I have the loom out, and pinned to a board to repair. I'm going to slowly work through, remove the outer insulation and check for burns/shorts.... here goes!

I'm half tempted to replicate the whole thing...


CS

[remta1]

great idea putting it on that board ..just going thru my dash resto now thanks for the advise

[Dino]

Oo I gotta steal that little trick!  I was just about to start cleaning up my power window loom so I'm glad I caught this!

[K9COP]

An 'Old Timer' likes one of my 'tricks'? I have arrived! LOL. Seriously though, it's the easiest way I found to keep track of what went where and what was damaged, without loosing my way and getting confused. (Happens a lot...     )

You might want to snip the cable (zip) ties though if you want to end the job with both eyes intact...   

Having gone through the whole harness, I think I'm going to replace the whole thing. There's so may hack jobs and crispy bits, doesn't seem worth the effort to put it back in. Up Next! CS rewires his whole car! 

CS

[Dino]

An 'Old Timer' likes one of my 'tricks'? I have arrived! LOL. Seriously though, it's the easiest way I found to keep track of what went where and what was damaged, without loosing my way and getting confused. (Happens a lot...     )

You might want to snip the cable (zip) ties though if you want to end the job with both eyes intact...   

Having gone through the whole harness, I think I'm going to replace the whole thing. There's so may hack jobs and crispy bits, doesn't seem worth the effort to put it back in. Up Next! CS rewires his whole car! 

CS

Hey I ain't that old!   

I agree, if it's been cut and if there's signs of heat damage then start over.

[K9COP]

[/quote]

Hey I ain't that old!   

I agree, if it's been cut and if there's signs of heat damage then start over.
[/quote]

Just calling it as I see it! LOL :

"Dino
Old Timer
*****
Online Online

Posts: 4,383"

I'm all for originality, but a burnt out, destroyed  'numbers matching' car with original wiring is worth much less to me than a fully functioning car with a new wiring loom in it. I'm with you brother.   

CS

[Dino]

Hey I ain't that old!   

I agree, if it's been cut and if there's signs of heat damage then start over.
[/quote]

Just calling it as I see it! LOL :

"Dino
Old Timer
*****
Online Online

Posts: 4,383"

I'm all for originality, but a burnt out, destroyed  'numbers matching' car with original wiring is worth much less to me than a fully functioning car with a new wiring loom in it. I'm with you brother.   

CS




[/quote]

Well I guess old is better than the alternative!   

Safety first, functionality next.  Originality ONLY if it makes sense.