The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 11-07-2004, 03:23 AM   #1
71Longbed
Not Mine But A beauty
 
71Longbed's Avatar
 
Join Date: Aug 2004
Location: Southern CaL
Posts: 368
electrical?

hello all having a littlebit of an electrical dilema truck starts up and runs fine the only thing is that when im driving it and come to a stop the lights and dash get dim and my sterreo shuts off and flickers someone told me it was a grounding problem current grounds i have put are to engine engine to chassay cab to chassy any help is appreciated also it only dims the lights when in drive
__________________
68 Chevy Shortbed 454/400
2000 Chevrolet Camaro SS 6spd
2011 Silverado 5.3 6spd auto
71Longbed is offline   Reply With Quote
Old 11-07-2004, 03:57 AM   #2
dyingdeadman
Registered User
 
dyingdeadman's Avatar
 
Join Date: Aug 2004
Location: san marcos,tx
Posts: 266
might be a weak alternater.
__________________
72 GMC sierra 3/4 ton 402 bb
68 GMC 3/4 ton
2010 camaro rs: daily driver
dyingdeadman is offline   Reply With Quote
Old 11-07-2004, 06:39 AM   #3
71Longbed
Not Mine But A beauty
 
71Longbed's Avatar
 
Join Date: Aug 2004
Location: Southern CaL
Posts: 368
i thought it was too i replaced it and same old bull im gonna check the voltage tho
__________________
68 Chevy Shortbed 454/400
2000 Chevrolet Camaro SS 6spd
2011 Silverado 5.3 6spd auto
71Longbed is offline   Reply With Quote
Old 11-07-2004, 07:44 AM   #4
GMCPaul
Senior Member
 
Join Date: Mar 2000
Location: Rockville,In. USA
Posts: 3,719
I'm assuming your running a alt. with a external regulator, if so remove the cover off external regulator and take a emery file and clean the points, then while cover is off start motor and turn on headlights and such to see if points close, if they don't close then the electrical system is getting all its juice from the battery and none from alt. at idle, so then take a allen wrench and adjust points setting so they go closed at idle with headlights on this will then brighten your lights at idle.
GMCPaul
GMCPaul is offline   Reply With Quote
Old 11-08-2004, 02:33 AM   #5
71Longbed
Not Mine But A beauty
 
71Longbed's Avatar
 
Join Date: Aug 2004
Location: Southern CaL
Posts: 368
using internal regulated alter nator off of a 1986-7 silverado
__________________
68 Chevy Shortbed 454/400
2000 Chevrolet Camaro SS 6spd
2011 Silverado 5.3 6spd auto
71Longbed is offline   Reply With Quote
Old 11-08-2004, 04:55 AM   #6
Brainchild
Still drivin' a Rat Rod
 
Brainchild's Avatar
 
Join Date: Sep 2004
Location: Monett Missouri
Posts: 4,925
Did you run the brown wire to a gauge or light when you converted it to internal regulator alt? If not that might be the problem.And did you convert it using the layout in the FAQ,I did mine from there and it works perfectly.

http://207.44.196.117/vboard/showthread.php3?t=119379
__________________
Rusty Member #13872
Instead of saying.....you are a discomfort in the back of my front.....one should be able to say...... you are a pain in the *a$#*

71 GMC LWB
49 Chevy
85 Chevy G20

Check out my website
Brainchild is offline   Reply With Quote
Old 11-08-2004, 05:15 AM   #7
71Longbed
Not Mine But A beauty
 
71Longbed's Avatar
 
Join Date: Aug 2004
Location: Southern CaL
Posts: 368
actually i didnt do this mod truk came that way when i got it im gonna check on it where should the brown wire be on my dash so i know
__________________
68 Chevy Shortbed 454/400
2000 Chevrolet Camaro SS 6spd
2011 Silverado 5.3 6spd auto
71Longbed is offline   Reply With Quote
Old 11-08-2004, 08:51 AM   #8
Blue Beard
Registered User
 
Blue Beard's Avatar
 
Join Date: Jan 2003
Location: Washington State
Posts: 8,834
Running about the same on mine, replaced alt and bat. About a week out the bat is so low, no good.

Keep us posted if you find out and I'll do the same.
__________________
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
Blue Beard is offline   Reply With Quote
Old 11-08-2004, 05:16 PM   #9
71Longbed
Not Mine But A beauty
 
71Longbed's Avatar
 
Join Date: Aug 2004
Location: Southern CaL
Posts: 368
ttt
__________________
68 Chevy Shortbed 454/400
2000 Chevrolet Camaro SS 6spd
2011 Silverado 5.3 6spd auto
71Longbed is offline   Reply With Quote
Old 11-13-2004, 04:20 AM   #10
71Longbed
Not Mine But A beauty
 
71Longbed's Avatar
 
Join Date: Aug 2004
Location: Southern CaL
Posts: 368
k guys fixed up the problem now for the gentlemen that says he has the same prob i took it down to the ol electric shop of a freind so it didnt cost me a thing we found out the the little box on the fender with the lights and battery hook the connections were pretty dirty and tattered so we cleaned em up and threw on new connectors turns out i was losing 1 volt and a half after this simple fix i was all set no more dim lights Yippee!! hope this solves it for you aswell
__________________
68 Chevy Shortbed 454/400
2000 Chevrolet Camaro SS 6spd
2011 Silverado 5.3 6spd auto
71Longbed is offline   Reply With Quote
Old 11-13-2004, 04:44 AM   #11
GMCPaul
Senior Member
 
Join Date: Mar 2000
Location: Rockville,In. USA
Posts: 3,719
Thumbs up

LOL so did your friend let you know when you were cleaning the terminals on the little black box that it was a external regulator for a externally regulated alternator. Any time you have dim headlights at idle the culprits almost always 99.9% of the time the external regulator for the alternator.
If your using a internally regulated alternator as you stated in earlier post off a late model truck you should not be using the external regulator at all, it should be by passed by connecting terminal #1 on plug for the external alternator to terminal #3, and connect terminal #2 to terminal #4, this effectively bypasses the regulator in the harness allowing you to use the internally regulated alternator. Without doing this you will experience the battery getting drained when truck off and sitting and other irritating electrical problems.
GMCPaul
GMCPaul is offline   Reply With Quote
Old 11-13-2004, 04:54 AM   #12
71Longbed
Not Mine But A beauty
 
71Longbed's Avatar
 
Join Date: Aug 2004
Location: Southern CaL
Posts: 368
im not sure were on the same page their paully my set up is internal regulated was done by an electronic sho i don't even have an external regulator in my truck where it use to be was on the radiator core support i trashed it during my engine reapainting session im talking about the little black box on the left fender my lights would only dim while idle in the drive position im unsure wut youre sayin but let me know im pretty sure the internal conversion is right 2 wires are joined and the harness for the external is just in the air since no external exist on my truck anymore
__________________
68 Chevy Shortbed 454/400
2000 Chevrolet Camaro SS 6spd
2011 Silverado 5.3 6spd auto
71Longbed is offline   Reply With Quote
Old 11-13-2004, 05:18 AM   #13
GMCPaul
Senior Member
 
Join Date: Mar 2000
Location: Rockville,In. USA
Posts: 3,719
Thumbs up

What little black box on the drivers side fender are you referring to?? there isn't supposed to be anything between the alternator & battery in the wiring except a fusible link built into the charging wire and a junction block on passenger fender where charge wire connects from alternator & where charge wire to battery connects & if a gauge truck a wire for alt. gauge?? The externally regulated harness is the one thats supposed to have the jumpers on it from #1 to #3 terminal & #2 to #4. Its possible the electric shop disconnected external regulator and then ran all new wiring for the internal alternator instead of using what already existed by adding jumpers as I described.
GMCPaul
GMCPaul is offline   Reply With Quote
Old 11-13-2004, 08:22 AM   #14
Blue Beard
Registered User
 
Blue Beard's Avatar
 
Join Date: Jan 2003
Location: Washington State
Posts: 8,834
Thanks GMCPaul for that post, My 70 has been giving me headaches with drainage problems for some time.

Replaced alot of bad wiring, but still have the problem. This gives me one more thing to try. No one has ever mentioned that before. Or the box issue.
__________________
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
Blue Beard is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:44 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com