ELECTRICAL short!!!!!!!!!!!! ????? wireing ???? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dandeluxe · 05-29-2004, 09:17 AM

WHERE IS THE BEST PLACE TO LOOK FOR A SHORT IN MY TAIL LIGHTS WIREING ? IT USUALLY TAKES ABOUT 20 MINUTES AFTER REPLACING A 25 AMP FUSE. I ALWAYS KNOW MY TAIL LIGHTS WENT OUT BECAUSE THE DOME LIGHT AND THE DASH LIGHTS AND THE TAIL LIGHTS GO OUT AT THE SAME TIME. COULD IT BE THE DASH LIGHTS CIRCUIT BOARD OR THE DOME LIGHT WIREING CAUSING IT ? ANY HELP AT ALL IS GREATLY APPRECIATED.
IS IT TRUE YOU CAN FIND A SHORT WITH A COMPASS BY RUNNING IT ALONG THE WIREING AND WATCH THE COMPASS AND SEE IF IT GOES WHACKY???? THANKS , DANDELUXE

MACKL · 05-29-2004, 09:31 AM

I would try taking as many cirucits out of the puzzle as possible. Unplug something and see if you still have the problem. Start with the conector for the tail/turn lights. If fuse still blows, move somewhere else.

cdowns · 05-29-2004, 09:33 AM

get under the truck along the drivers framerail the clips that hold the wire harness in place are a prime area for shorts you'll probably find them all dryrottyed and cracked along the whole length. if you go to a trailer or marine supply store you can buy the 4wiretrailer light wires by the foot for alot cheaper than a factory harness replace the wire from the firewall all the way back

**FRENCHBLUE72** · 05-29-2004, 09:46 AM

I had to do as cdown's suggested on my blazer had the same problem's as you described....

Sweet72 · 05-29-2004, 09:50 AM

The "compass gone crazy" idea is a little out there. I use multimeters everyday on the job to find electrical shorts. The easiest way for a novice electrician is as MACKL stated above... start isolating segments of the circuit. Unplug the rear lighting connector at the last crossmember and then energize the circuit to see if the fuse blows, and if not, just keep unplugging sections of the circuit till fuses stop blowing. A schematic will be necessary to find out what all is powered by that fuse.
BTW: The short is intermittent if it takes that long for the fuse to blow, and as stated by cdowns, It's probably the segment between the firewall connector and the rear lighting plug chaffing at one of the metal clips along the frame rail. Good luck...

Dandeluxe · 05-31-2004, 12:59 PM

SWEET 72, FRENCHBLUE72, CDOWNS, & MACKL,
THIS BOARD ROCKS. THANKS SO MUCH FOR THE INFO. I'M GONNA TRY GETTING UNDER AND LOOKING AT ALL THE WIREING ON THE FRAME RAIL. AND TRY UNPLUGGING ONE CIRCUIT AT A TIME UNTIL I FIGURE IT OUT. IT'S PROBABLY OLD DRYROTTED WIREING.

THANKS AGAIN, DANNY C.

05-29-2004, 09:17 AM	#1
Dandeluxe Senior Member Join Date: Nov 2001 Location: st.louis mo. Posts: 717	ELECTRICAL short!!!!!!!!!!!! ????? wireing ???? WHERE IS THE BEST PLACE TO LOOK FOR A SHORT IN MY TAIL LIGHTS WIREING ? IT USUALLY TAKES ABOUT 20 MINUTES AFTER REPLACING A 25 AMP FUSE. I ALWAYS KNOW MY TAIL LIGHTS WENT OUT BECAUSE THE DOME LIGHT AND THE DASH LIGHTS AND THE TAIL LIGHTS GO OUT AT THE SAME TIME. COULD IT BE THE DASH LIGHTS CIRCUIT BOARD OR THE DOME LIGHT WIREING CAUSING IT ? ANY HELP AT ALL IS GREATLY APPRECIATED. IS IT TRUE YOU CAN FIND A SHORT WITH A COMPASS BY RUNNING IT ALONG THE WIREING AND WATCH THE COMPASS AND SEE IF IT GOES WHACKY???? THANKS , DANDELUXE __________________ 1969 cst swb 350/400 th . DANNY C . ["]FRIENDS DONT LET FRIENDS DRIVE F@RD$!! 1969 cst swb corvette hugger orange with 400 hp sbc I started out with nothing and i held on to it

05-29-2004, 09:31 AM	#2
MACKL Almost done! Join Date: Apr 2004 Location: Woodstock GA Posts: 193	I would try taking as many cirucits out of the puzzle as possible. Unplug something and see if you still have the problem. Start with the conector for the tail/turn lights. If fuse still blows, move somewhere else. __________________ The 1970 SWB Project Removed 6cyl manual trans, manual everything V8-350 Auto/PS/PDB Blazer Fuel Tank Behind the Marker Light Fuel Fill

05-29-2004, 09:33 AM	#3
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	get under the truck along the drivers framerail the clips that hold the wire harness in place are a prime area for shorts you'll probably find them all dryrottyed and cracked along the whole length. if you go to a trailer or marine supply store you can buy the 4wiretrailer light wires by the foot for alot cheaper than a factory harness replace the wire from the firewall all the way back __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

05-29-2004, 09:46 AM	#4
FRENCHBLUE72 PROJECT 7DEUCE Join Date: Dec 2002 Location: GRANTS PASS OR Posts: 21,608	I had to do as cdown's suggested on my blazer had the same problem's as you described.... __________________ GO BIG GREEN GO DUCKS MEMBER #6377 72 k-5 daily driver 6'' lift 35'' 350-350-205 slowly getting rust free. Project "7DEUCE" check out my build http://67-72chevytrucks.com/vboard/s...d.php?t=267665 Tim Powell..R.I.P EastSideLowlife..... R.I.P..

05-29-2004, 09:50 AM	#5
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	The "compass gone crazy" idea is a little out there. I use multimeters everyday on the job to find electrical shorts. The easiest way for a novice electrician is as MACKL stated above... start isolating segments of the circuit. Unplug the rear lighting connector at the last crossmember and then energize the circuit to see if the fuse blows, and if not, just keep unplugging sections of the circuit till fuses stop blowing. A schematic will be necessary to find out what all is powered by that fuse. BTW: The short is intermittent if it takes that long for the fuse to blow, and as stated by cdowns, It's probably the segment between the firewall connector and the rear lighting plug chaffing at one of the metal clips along the frame rail. Good luck... __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction. Last edited by Sweet72; 05-29-2004 at 10:15 AM.

05-31-2004, 12:59 PM	#6
Dandeluxe Senior Member Join Date: Nov 2001 Location: st.louis mo. Posts: 717	short!!!!!!!!!!!!!!! SWEET 72, FRENCHBLUE72, CDOWNS, & MACKL, THIS BOARD ROCKS. THANKS SO MUCH FOR THE INFO. I'M GONNA TRY GETTING UNDER AND LOOKING AT ALL THE WIREING ON THE FRAME RAIL. AND TRY UNPLUGGING ONE CIRCUIT AT A TIME UNTIL I FIGURE IT OUT. IT'S PROBABLY OLD DRYROTTED WIREING. THANKS AGAIN, DANNY C. __________________ 1969 cst swb 350/400 th . DANNY C . ["]FRIENDS DONT LET FRIENDS DRIVE F@RD$!! 1969 cst swb corvette hugger orange with 400 hp sbc I started out with nothing and i held on to it



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