Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1973 - 1979 F-100 & Larger F-Series Trucks
Sign in using an external account
Register Forgot Password?


1973 - 1979 F-100 & Larger F-Series Trucks Discuss the Dentsides Ford Truck

Welcome to Ford-Trucks Forums!
Welcome to Ford-Trucks.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Ford-Trucks Forums community today!





 
Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 12-02-2010, 10:08 PM
nathanstephanie nathanstephanie is offline
New User
 
Join Date: Dec 2010
Posts: 4
nathanstephanie is starting off with a positive reputation.
what is causing my lights to flicker at idle?

hey guys, my lights flicker at an idle, i have checked the voltage rgulator under the hood, thebattery and the alternator and all are good. an old timer told me that i had a voltage regulator behind the dash, but its not in the chiltons and i cant find it. any advise???
Reply With Quote
  #2  
Old 12-02-2010, 10:21 PM
HIO Silver's Avatar
HIO Silver HIO Silver is offline
Post Fiend
 
Join Date: Dec 2009
Location: NorCal
Posts: 10,841
HIO Silver is a splendid one to beholdHIO Silver is a splendid one to beholdHIO Silver is a splendid one to beholdHIO Silver is a splendid one to beholdHIO Silver is a splendid one to beholdHIO Silver is a splendid one to beholdHIO Silver is a splendid one to behold
C'mon man, ya gots to be a little more specific so we can help you out..... Do you mean the headlights or the dash (instrument) lights? By discussing the VR, then I presume you're talking about the dash lights.

Please clarify. Thanks!
__________________
73 F100 SB, 4x4, 390FE, NP435, +4 on 35s, 71 F250 LB, 2wd, 360FE, T-18, 70 F100 LB, 2wd, 360FE-EFI, TKO-500, 76K original miles, 01 F150 SuperCrew Lariat 4x4, 5.4L, 01 PT Cruiser Limited (DD), 71 Pontiac Lemans Sport Convertible, 68 Mustang 200-1v, 65 Mustang 289-4v
Reply With Quote
  #3  
Old 12-03-2010, 02:32 PM
steponit steponit is offline
Elder User
 
Join Date: Apr 2009
Posts: 735
steponit is gaining momentum as a positive member of FTE.
The Voltage regulator behind the dash is for the gauges and warning lights

It is called a Instrument cluster Voltage regular and has NOTHING to do with flickering lights

Your problems can be caused by a few things

1) Bad grounding of all associated parts
2) bad headlight switch
3) corroded connections
4) Bad Voltage Regulator
Reply With Quote
  #4  
Old 12-03-2010, 06:23 PM
nathanstephanie nathanstephanie is offline
New User
 
Join Date: Dec 2010
Posts: 4
nathanstephanie is starting off with a positive reputation.
fickering lights in cab, and headlights

yes the dome light flickers inside the cab when it is on andthe truck is at an idle, also the headlights when the truck is at an idle. I have checked every ground i can find. It really all leans toward the VR under the hood. its gotta be something real simple, driving me NUTS! Thanxs for all the input i really appreciate it!
Reply With Quote
  #5  
Old 12-03-2010, 07:33 PM
steponit steponit is offline
Elder User
 
Join Date: Apr 2009
Posts: 735
steponit is gaining momentum as a positive member of FTE.
You have to check the Mounting of the VR for corrosion and make sure the mating areas are clean and secure
Reply With Quote
  #6  
Old 12-04-2010, 05:26 PM
Don S.'s Avatar
Don S. Don S. is offline
Elder User
 
Join Date: Aug 2007
Location: S'Dale Wa.
Posts: 543
Don S. is starting off with a positive reputation.
Make sure your idle is set properly too low and that the belt is tensioned properly as these too can cause lights to pulsate.
__________________
Committee: a group of the unwilling, picked from the unfit, to do the unnecessary.

"Brutus" 1978 F-150 SC 4x4 BB460

" There is a very fine line between "hobby" and "mental illness."
" -Dave Barry, Nationally Syndicated Columnist
Reply With Quote
  #7  
Old 12-04-2010, 05:39 PM
hairyboxnoogle's Avatar
hairyboxnoogle hairyboxnoogle is offline
Postmaster
 
Join Date: Apr 2008
Location: Jordan Valley, OR
Posts: 4,935
hairyboxnoogle is gaining momentum as a positive member of FTE.
ranger_nog hairyboxnoogle
Is there anything causing a drain on the battery? Something aftermarket like an amplifier can cause this, especially in these older trucks as the alternator doesnt begin to fully charge until around 1200+ rpms.
__________________

'92 F-250 XLT
- Supercab, 4x4, ZF, 7.3 ATS 088, D50 SAS-PMF 2.25" RSK / 10.5LS, SD e-fuel, HPC e-fans
Reply With Quote
  #8  
Old 12-04-2010, 05:47 PM
jimjoe56 jimjoe56 is offline
New User
 
Join Date: Sep 2010
Posts: 2
jimjoe56 is starting off with a positive reputation.
Make sure that you have a ground strap from the block to the frame. Fixed my flickering lights
Reply With Quote
  #9  
Old 12-06-2010, 02:04 PM
81-F-150-Explorer 81-F-150-Explorer is offline
Post Fiend
 
Join Date: Jul 2004
Location: Northern California
Posts: 8,791
81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold
You should also have a ground strap from the engine to firewall.

The voltage regulator needs to be grounded. It grounds to its mounting surface. Make sure it's clean and tight as steponit said.

The altenator brushes can be severly worn and cause this at an idle.
Reply With Quote
  #10  
Old 12-06-2010, 02:26 PM
Nathan Plemons Nathan Plemons is offline
Elder User
 
Join Date: Aug 2004
Posts: 781
Nathan Plemons is gaining momentum as a positive member of FTE.
Gotta agree with pretty much everything that has been posted so far. The alternators on these trucks are not extremely high powered, you're talking around 61 amps tops. Any alternator at idle puts out well less than it's rated maximum.

Just as an example, Powermaster lists their 140 alternator only puts out 80 amps at idle. That's only 57% of rated output. Their 200 amp unit only puts out 120 at idle, 60%.

So if you wanna be on the optimistic side and say your alternator puts out 60 amps at full speed, then it puts out 60% of this at idle, you're talking only 36 amps. A typical headlight is around 60 watts at 12.8 volts. That's 9.3 amps for the pair. Even if you're not powering anything else but the ignition system you've only got 25 amps worth of capacity. Couple that with a questionable ground here and there and a little bit of corrosion on a few connections, a marginal battery, then suddenly you've got a whole slew of electrical problems even though your alternator and voltage regulator may be just fine.

Anywho, you're wasting your time chasing that mysterious behind the dash voltage regulator. It deals only with your instruments and will have no impact on your headlights, dome light, etc. You need to disconnect and clean every contact on your alternator and make sure that all of your connections there are solid. You need to do the same thing with your voltage regulator and make sure that it has a very solid ground. Use a meter and measure the resistance from the voltage regulator's mounting point over to your negative battery post. If that resistance is anything more than around 0 you need to re-work it. Make sure your negative battery cable is clean, free of corrosion, and tight and goes directly to your engine block. Then you need to make sure that there is a solid ground from the block to the frame and also to the chassis. The positive cable needs to also be free of corrosion and clean. Just because it "looks" clean doesn't necessarily mean that it is. Take everything apart hit it with contact cleaner and a wire brush, steel wool, sandpaper, SOMETHING to clean them up. And finally make sure your battery is fully charged so it can kinda act as a buffer for when your alternator falls short.

An alternator really is a lousy battery charger and if your charging system is anything less than perfect it will not keep your battery fully charged. Put a smart charger on your battery and let it bring it up to full charge slowly. You will probably be surprised at how low it thinks your battery really is.
Reply With Quote
  #11  
Old 12-06-2010, 03:02 PM
81-F-150-Explorer 81-F-150-Explorer is offline
Post Fiend
 
Join Date: Jul 2004
Location: Northern California
Posts: 8,791
81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold81-F-150-Explorer is a splendid one to behold
Quote:
Originally Posted by Nathan Plemons View Post
Make sure your negative battery cable is clean, free of corrosion, and tight and goes directly to your engine block.
The Factory wiring on the 300-6 the negative battery cable goes from the battery Negative terminal, and goes directly to the starter mounting bolt where it bolts to the engine. If the starter mounting surface to the engine is not really clean or good, this can cause a poor ground to the engine.

Also midpoint on this cable there is a tab that attaches the cable to the frame. This is how the frame is grounded from the factory.

Make sure these are clean and tight, and present, as replacement cables do not have the tab on the cables to ground the frame, so you will have to improvise something.
Reply With Quote
  #12  
Old 12-06-2010, 04:25 PM
Nathan Plemons Nathan Plemons is offline
Elder User
 
Join Date: Aug 2004
Posts: 781
Nathan Plemons is gaining momentum as a positive member of FTE.
Hmm, didn't know that about the straight 6. The cable on my 302 goes straight to the block kinda behind and below the alternator. I guess if it were me trying to replace the cable I would go for a nice solid cable right from the battery cable to the starter bolt and then use a second cable to come back to the frame.
Reply With Quote
Old 12-06-2010, 04:25 PM
 
 
 
Reply

Go Back   Ford Truck Enthusiasts Forums > Older, Classic & Antique Trucks > 1973 - 1979 F-100 & Larger F-Series Trucks

Tags
1977, bad, battery, cluster, f150, flicker, flickering, ford, idel, idle, idling, instrument, lights, pulsate, truck

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery light flickering while driving Pocket 1999 - 2003 7.3L Power Stroke Diesel 21 11-18-2013 03:06 PM
voltage readings? mustang9701 1999 - 2003 7.3L Power Stroke Diesel 5 03-11-2013 08:44 AM
Battery light flickering cutlass 1999 - 2003 7.3L Power Stroke Diesel 14 09-23-2012 11:17 PM
NEW ALTERNATOR NEW PROBLEM mstiles19 Super Duty & Heavy Duty 15 04-11-2010 01:23 PM
flickering alternator light dbuck50 1987 - 1996 F150 & Larger F-Series Trucks 15 12-26-2007 03:06 PM



All times are GMT -5. The time now is 04:17 PM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Advertising - Terms of Use - Privacy Statement - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup