dimming lights

reignman · 11-25-2002, 07:48 PM

when i am at idle my lights dim in my panel and my volts go down they use to go back up but now it only sometimes goes up is this my alternator or my battery i dont know how old easch one are

BLACK85GT · 11-25-2002, 08:04 PM

could be alternator, or voltage regulator. Autozone checks them for free.

5.0L_Of_Fury · 11-26-2002, 02:05 PM

my car does same thing...alternator is fine brand new bat..chaning regulator this afternoon...will let ya know if it fixes it

corder13 · 11-30-2002, 11:22 AM

Did the regulator fix it?

Rick

PKRWUD · 11-30-2002, 03:13 PM

Sounds like a stock alternator on an engine with underdrive pullies to me.

Take care,
~Chris

MidNiteBlu 5.0 · 11-30-2002, 04:55 PM

Mine usually does that if it idles below 800 rpm. After that it goes back up and stays up while im driving. I have a brand new alternator too. I think the 75 amp stockers arent that strong. i wanted to do a 130 but didnt have the time cause i needed my car to run.

84LX89GT · 11-30-2002, 08:40 PM

Do you have a good ground from the block to the chassis? I changed battery cables, when i had my '84 and the lights would dim at low rpm. I added a ground cable from the block to the chassis and everything worked great again. Just something to consider.
Most likely though it's a weak alternator/regulator.

gofastmercury · 12-01-2002, 05:58 PM

My mustang just started doing this as well. But its not just at idle, its any time. I was thinking its just a bad conection or ground, but havn't had the time to look for it.

Waiting for your answer...

11-25-2002, 07:48 PM	#1
reignman Registered Member Join Date: Oct 2002 Location: cincinnati ohio Posts: 24	dimming lights when i am at idle my lights dim in my panel and my volts go down they use to go back up but now it only sometimes goes up is this my alternator or my battery i dont know how old easch one are __________________ 92 Lx Flowmaster pipes, but no other mods 110,000 miles rookie mustang owner

11-25-2002, 08:04 PM	#2
BLACK85GT Registered Member Join Date: May 2002 Location: Tampa,FLORIDA Posts: 340	could be alternator, or voltage regulator. Autozone checks them for free. __________________ 5.0, Holley heads, 1.7 Scorp Rockers, Stealth intake, Holley 600 carb, Holley Mech. Fuel pump, MSD 6Digital, MSD distributor, Hotchkis upper/lower rear control arms, FMS B Springs, 3:73 (8.8) rear. Production # 9,377

11-26-2002, 02:05 PM	#3
5.0L_Of_Fury Registered Member Join Date: May 2001 Location: Mayfield,KY,USA Posts: 288	my car does same thing...alternator is fine brand new bat..chaning regulator this afternoon...will let ya know if it fixes it __________________ OLD NAME:4cyl_Of_Fury 1990 LX 5.0 Hatchback K&N,March Ram Air,Strut Tower Brace '93LX Hatchback !FOR SALE No Substitute For Cubic Inches! BURN EM UP fivepointzero@kytnar.org "Give 'Er Hell" "They Call It Minute Rice..Gee Are Those Actually Track Times?" Firemen: We Find 'Em Hot And Leave 'Em Wet" Rice Haters Club Member #23 (GM Ricer Fads) Gotta Love Hatin 'Em CLUTCHES,FUEL PUMP RELAYS,FOUR CYLINDERS

11-30-2002, 11:22 AM	#4
corder13 Registered Member Join Date: Nov 2002 Location: Jonesburg, MO USA Posts: 8	Did the regulator fix it? Rick __________________ If anyone wants to trade their 5.0 HO, 5 speed 'Stang for my '86 TC (with every option but sunroof), please let me know!!!

11-30-2002, 03:13 PM	#5
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Sounds like a stock alternator on an engine with underdrive pullies to me. Take care, ~Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

11-30-2002, 04:55 PM	#6
MidNiteBlu 5.0 I got something to say Join Date: Sep 2001 Location: San Diego, CA Posts: 1,557	Mine usually does that if it idles below 800 rpm. After that it goes back up and stays up while im driving. I have a brand new alternator too. I think the 75 amp stockers arent that strong. i wanted to do a 130 but didnt have the time cause i needed my car to run. __________________ 91 LX Hatch 5.0 - made for the twisties 89 LX Hatchback 5.0 5spd. stolen/stripped 4/7/05 http://www.mustangworks.com/cgi-bin/...splay.cgi?3494 1987 Toyota Pickup Ricer Haters Club Member #33 Want a custom gauge cluster for your Vintage Mustang? www.jmeenterprises.com

11-30-2002, 08:40 PM	#7
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	Do you have a good ground from the block to the chassis? I changed battery cables, when i had my '84 and the lights would dim at low rpm. I added a ground cable from the block to the chassis and everything worked great again. Just something to consider. Most likely though it's a weak alternator/regulator. __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

12-01-2002, 05:58 PM	#8
gofastmercury Registered Member Join Date: May 2001 Location: calgary alberta canada Posts: 366	My mustang just started doing this as well. But its not just at idle, its any time. I was thinking its just a bad conection or ground, but havn't had the time to look for it. Waiting for your answer... __________________ 93LXcopcarSOLD14.3@96 @ 4500ft 2.02 60ft on street tires. my 67 ranchero NOT A 390 ANY MORE! 460! 3.70's cast manifolds, comp cams 262H, performer, 750DP 100K out of 79 F250 NEW(oct20/02)14.58@95mph 2.3 60 ft corrects to:13.86@100 66 merc comet351w, isky roller 600 lift 268/260@.050, vic jr. 700DP, 5000stall, 4.56's c-4, 3400lbs with driver 12.3@110 @ 4000ft 1.69 60 ft corrects to:11.69@115

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