Dash lights

[boxboy]

Now what? I put in some new 1 candle power bulbs for the dash lights this morning, and the copper strip that connects them melted and bubbled up! Is there a way to repair this, or do I have to get a whole new instrument cluster somewhere? Why did it melt? I don't know. I played with it a week ago testing bulbs to see which ones worked and which ones not. How can I keep it from shorting out elsewhere now that the strip is peeling back a bit from where it shorted? Any advice appreciated.

[wayno]

Hi there Boxboy, Are you sure it was you that melted it, if so, then your going to have to find the short before putting in a new one. you also need to check the fuse, it should of blown, is it the right fuse for that part of the harness? I heard there was a 521 in the foster road pick and pull a while back, maybe it was in the holding yard, that one might still have a cluster in it, if not let me know, I have a extra or two. :) wayno

[boxboy]

Yeah, I saw the smoke and smelled it. You mean to say there is a short somewhere in the wiring, or in the board itself? I can see where it burnt, and have glued the strips back down so they won't short circuit anything else on the board.

 

I did wash the engine compartment yesterday. Could I have shorted something there that caused the circuit board to have problems? Can I just put some solder on it to reconnect that circuit?

[wayno]

Hi there Boxboy, It melted down for some reason, the fuse is probibly of to high an amperage also, it should of blown before melting the cluster circit board, I have a board that did the same thing to someone in the past, I have not tried to fix it, I just put in another guage cluster. These old trucks have seen so many owners and years of abuse, It is hard to say what has been changed in them(wiring) to accomidate radios, fog lights, ect. Somewhere in that dashlight wiring system there is a short of some type, and the fuse is of to high of amperage(????), so the next weakest area it seems, is them thin circut board copper strips/wires. Before you put the cluster back in, test the dash light circut with a battery, find the common ground on the board for the dash lights, then find the prong that supplys the power to the dash lights and see if they light up, and/or melt down again, that way if there is a fire, it won't be in your truck. wayno

[MikeRL411]

Locate the ends of the copper strip that melted, remove the "bubbled" length, scrape off the insulating varnish from the "good" ends. Then apply a small bit of flux and lightly tin the scraped ends. Take braided wire, tin the ends and replace the burnt out section you just removed. Solid wire would work, but is likely to crack under vibration. Cover the soldered joint with "Glyptol" insulating liquid [usually a sickening purple color], get it at Radio Shack, to prevent inadvertent shorts to the repair. Go to "Olddatsuns.com" and see what the proper size for the dash lights is and be sure to have the right sized fuse. Last year someone posted an LED light conversion for dash lamps, might be a safer alternative than 6 one candlepower lamps.

[danfiveten]

Its out in the yard.

[boxboy]

I've replaced all of the fuses with the correct sizes according to the FSM. So I don't think that is it. Thanks MikeRL411 for the 'how to' on the soldering. The question is, do I not use anything electrical on the truck until its fixed? Could I end up burning out other circuits like the gauges, the turn signals and all of that? If it is just the panel lighting, I can live without for a while.

[wayno]

hi there Boxboy, There is a datsun 521 at the foster pick and pull with a gauge cluster in it, the gauges in it will probibly work on your 520, if not you can transfer yours into that cluster. I would trace all the wires around the radio area just in case someone in the past put a radio in that needed a power wire for an internal light that worked off the dash lights. wayno

[datzenmike]

I think there is a narrow spot on one of the runs on the printed circuit that is intended to 'blow' if overloaded. Not totally sure but I think I've seen one before. If you were messing with the light bulbs last I would begin my search for a problem there. Maybe when screwing the light bulb plug in you have peeled up the copper. Additionally the tiny wire leads on the glass bulb may have moved andare touching something they shouldn't. I would remove them all and inspect before fixing the burnt out area or it will just fry somewhere/something else.

[boxboy]

Yeah, I am thinking it is NAPA giving me the wrong bulbs. I have power on the circuit before the burn out. No other gauges or lights affected. I need to find out what bulb is the right one. I even took the old ones in with me and they are still wrong. I don't know how spendy the LED system would be to make up, but I am thinking there has to be a way to by-pass the printed circuit. Seems like a real weak spot to me. I double checked all the connections and I think datzenmike is correct and it has to do with the bulb or the fixture that I was playing around with. It would seems strange to me if something upstream caused the burn out. Seems to me the short had to be downstream to cause it to overdraw power. Not driving a lot now, and hardly ever at night, so I won't sweat it too much til I have some more $$ to spend.

 

Thanks for the help.

[Unclejesse88]

It's the wattage of the bulb that matters. From there you can figure out the current draw (amps) of the bulb. Multiply that by six and you will most likely see why the printed circuit fried. Usually the bulbs will have a number printed on them, from there you can get the specs.

[boxboy]

The bulbs I took out (old ones) said 3 watt. The ones napa gave me to replace them had no wattage specified and nothing on the bulb. Just "one candle power". That is why i am betting on the bulb. If any one knows what the right bulb is and where I can get it, let me know. There are 3w and 5w in the board depending on application.

[boxboy]

Anyone got any idea what the bulb #s are and where to look for them? Like I said, NAPA gave me what they thought "looked right", and it shorted my system. Part #'s would be nice to be sure.

[ggzilla]

What is 1 candlepower?

 

The 620 instrument panel bulbs should be 1.7 watts 14V. They are pretty dim. Even worse, the common Type 159 is only 1.0 watt so it gets even dimmer.

 

Maybe later 620s used the Type 158 3.4 watt bulbs?

[elmerfudpucker]

I don't know how spendy the LED system would be to make up,

 

Not that spendy at all if you know who to talk to! ;) PM me.

[hang_510]

Locate the ends of the copper strip that melted, remove the "bubbled" length, scrape off the insulating varnish from the "good" ends.

:thumbup:

 

i prefer to use silver conductive paint for these types of repairs...

[hang_510]

What is 1 candlepower?

[MikeRL411]

Look below in the How To section for instrument panel LED replacement lamps. Plug in replacements [less the color filter if you have to remove them].

[banzai510(hainz)]

I would think if it was working before the bulb switch then maybe to many watt bulbs is the suspect and if mike said the trace is weak in one area.

I wouls fix the trace by scraping farther upo the pather then plice in a small gauge wire acrossed(bridged) it. The put the stock bulb back in.

 

Maybe Leds are better solution if low watt bulb are needed.

[mklotz70]

While working on Paula's lights, I put the gauge cluster back in with the lights on....touched something...burned the run. Soldered it....did it again...what a dumb *ss!! :) I then soldered a jumper wire across the burned area and removed power before putting the cluster back in.

 

Cluster for the 520 and 521 are the same.