backup lights don't work - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gman · 01-19-2004, 03:22 AM

Looking for some advise on where to begin looking to fix this. Bulbs are new and no fuses are blown. Looked at the wiring and it appears in good shape but I'm uncertain what to check to make sure. I'm no electrician. Any ideas would be appreciated on where to look first, second, third, etc.

gman · 01-19-2004, 03:23 AM

Forgot to mention its a 4 speed manual floor tranny.

71chevylongbed · 01-19-2004, 03:26 AM

i got that same problem except my tranny is a th350 automatic

Hooter · 01-19-2004, 03:58 AM

um check to see if it plugged into the tranny first of all, if it is, the plug could be corroded or broken, or the switch in the tranny could be broke too

Longhorn Man · 01-19-2004, 08:19 AM

The 4 speed should have a light green wire under the truck to the tranny...I think on the drivers side. That'll be the wire that goes to the tail lights.
On the TH350 truck, it'll be at the bottom of the steering column inside the cab, same light green wire.
If the wire is plugged in when you go out to inspect it, unplug it and if the corrosion is minimal, then apply 12 volts to it and see if the lights come on. If they do, then you have switch problems, if they don't, you have a wire problem south of the switch. (Asuming you have bulbs and grounds)

Blue Beard · 01-19-2004, 09:04 AM

are the sockets in good shape..?

mine are sometimes, others its like they jiggle loose.....

gman · 01-20-2004, 11:55 AM

Thanks.........as soon as it gets above 25 or 30 degrees for more than an hour I'll climb under there and check that out. Just from memory, I don't remember any light green wire leaving the tranny and going to the rear of the truck. Longhorn man...........you don't happen to know what side of the truck it'll be on and I'm assuming it will be routed down the frmae rail? Thanks again.

gman · 01-20-2004, 11:56 AM

Ooops...........reread the thread and see you stated the drivers side. Thanks!

01-19-2004, 03:22 AM	#1
gman Registered User Join Date: Nov 2000 Location: Ogden, Utah Posts: 290	backup lights don't work Looking for some advise on where to begin looking to fix this. Bulbs are new and no fuses are blown. Looked at the wiring and it appears in good shape but I'm uncertain what to check to make sure. I'm no electrician. Any ideas would be appreciated on where to look first, second, third, etc. __________________ 72 Chevy SWB Custom Deluxe K10, 350/SM465, PS, PB, Fact. Air 2000 Harley...Wide Glide

01-19-2004, 03:23 AM	#2
gman Registered User Join Date: Nov 2000 Location: Ogden, Utah Posts: 290	Forgot to mention its a 4 speed manual floor tranny. __________________ 72 Chevy SWB Custom Deluxe K10, 350/SM465, PS, PB, Fact. Air 2000 Harley...Wide Glide

01-19-2004, 03:26 AM	#3
71chevylongbed Got Horsepower? Join Date: Sep 2003 Location: IDAHO Posts: 406	i got that same problem except my tranny is a th350 automatic __________________ 2001 Dodge 2500 Cummins, 4 inch lift, 35" Toyo MT's on Ultra wheels, P-Pump Conversion, AFE intake, Fass, 5 inch exhaust, Pyro,Boost,and Fuel pressure guages, and a whole bunch of other stuff "The Money Pit" SOLD-71 Chevy C10 long bed- 2/4 drop-- 350,th400, Edelbrock performer RPM intake,Edelbrock 600 CFM carb,Crower 240 cam,port and polish,Dynomax headers,HEI ignition,dual 2.5 inch exhaust with Flowmaster 50 series mufflers

01-19-2004, 03:58 AM	#4
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,085	um check to see if it plugged into the tranny first of all, if it is, the plug could be corroded or broken, or the switch in the tranny could be broke too __________________ Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life

01-19-2004, 09:04 AM	#6
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	are the sockets in good shape..? mine are sometimes, others its like they jiggle loose..... __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

01-19-2004, 08:19 AM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	The 4 speed should have a light green wire under the truck to the tranny...I think on the drivers side. That'll be the wire that goes to the tail lights. On the TH350 truck, it'll be at the bottom of the steering column inside the cab, same light green wire. If the wire is plugged in when you go out to inspect it, unplug it and if the corrosion is minimal, then apply 12 volts to it and see if the lights come on. If they do, then you have switch problems, if they don't, you have a wire problem south of the switch. (Asuming you have bulbs and grounds)

01-20-2004, 11:55 AM	#7
gman Registered User Join Date: Nov 2000 Location: Ogden, Utah Posts: 290	Thanks.........as soon as it gets above 25 or 30 degrees for more than an hour I'll climb under there and check that out. Just from memory, I don't remember any light green wire leaving the tranny and going to the rear of the truck. Longhorn man...........you don't happen to know what side of the truck it'll be on and I'm assuming it will be routed down the frmae rail? Thanks again. __________________ 72 Chevy SWB Custom Deluxe K10, 350/SM465, PS, PB, Fact. Air 2000 Harley...Wide Glide

01-20-2004, 11:56 AM	#8
gman Registered User Join Date: Nov 2000 Location: Ogden, Utah Posts: 290	Ooops...........reread the thread and see you stated the drivers side. Thanks! __________________ 72 Chevy SWB Custom Deluxe K10, 350/SM465, PS, PB, Fact. Air 2000 Harley...Wide Glide



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