Question about 2005 Ford F-150

1 Answer

Dim or pulsating headlights at low rpm

The headlights and dash panel lights in my truck pulsate at low rpm (idle) and occasionally on long distance at highway speeds I've noticed a strange sound in conjunction with a momentary spike or overcharge reading on the dash panel charging gauge. Is this indicative of a bad voltage regulator?

Posted by on


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that gotĀ 5 achievements.


    An expert that hasĀ over 500 points.


    An expert who has answered 200 questions.

  • Expert
  • 208 Answers

Go to your local auto zone they will put a check on the battery, most likley the altanator is going out but it could be the battery, they can check it while it is in the vehicle

Posted on Nov 26, 2013


6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017

  • 14 Answers

SOURCE: High temperature gauge reading, low battery voltage reading

The loud whine you speak of indicates one of two things a bad serpentine belt or alternator, The first thing would be to check the belt.Look for cracks worn spots or glazing. If the belt looks ok then take the belt off and start the engine for a minute or so and listen for noise.

Posted on Jan 01, 2009

  • 783 Answers

SOURCE: My 2000 Ford Taurus at about 4000 rpm does not go

To do this in park or neutral is normal. To do it while driving is not.
There are so many things that could cause this but if you have no check engine light and it runs normally up until then I would suspect you have an exhaust restriction. This can be checked fairly easy on this vehicle, it has a DPFE sensor that mounts near the top back side of the motor.It will either be black or silver,will have a 3 wire connector to it and 2 hoses going down the back of the motor to the exhaust. You can disconnect one of these hoses and install a vacuum/pressure guage and measure exhaust back pressure. It should be 1 psi or less at idle and when you go to wide open throttle should not exceed 3 to 4 psi. If it does something in exhaust,most likely one of the catalytic convertors is stopped up.

Posted on Feb 19, 2009

  • 1986 Answers

SOURCE: 98 expedition battery light comes on with increase of rpm

There may be no loss of voltage, but is there a surge of voltage?

As for the battery itself when tested, it should read 12-12.5Volts across the
leads when the car is off. When the car is running, the battery should be reading 13-14Volts across the leads, anything lower means the alternator is not charging your battery, anything higher means the alternator is over charging and damaging your battery.

Another cause for the battery light could be your ECU has detected an error

Posted on Aug 20, 2009

Testimonial: "thanks, haven't seen a alternator discharge light go on and off, normally it's either worked or didn't"

  • 819 Answers

SOURCE: low oil presure

perform a master oil pressure test. this is done by removing the oil pressure sending unit and installing a oil pressure gauge. if the reading on the test gauge is ok, the sending unit needs to be replaced. if the pressure reads low on the test gauge, there may be excessive bearing wear or you may have worn valve guides. good luck!

Posted on Apr 29, 2010

  • 8836 Answers

SOURCE: 2004 F350 dually crewcab turbo

Below is your wiring diagram. So does the battery run down or not? At 12 volts, the battery should run down. Here are a couple things to check. The grey 20 gage fusible link from the battery to the alternator runs the stator coil. You could try jumping that with a regular 14 gage wire to see if the voltage will jump up (should be at least 14 volts). The other thing is with dual batteries (which I think you have), if one battery is bad, it could pull down your voltage. Try unhooking the negative terminal on one battery at a time to see if the voltage increases. Let me know if you have any questions.


Posted on Dec 06, 2010

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Hello...I have a 2009 chevy cruze 1.8L ,some 3 months ago,the car had some pulsating and vibration during driving , so I changed the spark plugs and the problem was solved, but after about a month,the car...

Was any of the previous spark plugs fouled? Dirty? If so you need to investigate whether the problem is oil or fuel causing the fouling. Also a possibility is that you have a bad plug wire and when you changed plugs you disrupted the plug wire enough to make contact. Now possibly the plug wire is showing too much resistance causing a misfire at idle. Only way to be sure is to have the car scoped to see if the wires are proper or defective. That is unless you are the change parts and try type. In that case try a new set of wires. The reason is because at idle the voltage is not as high as it would be at higher rpm.

Aug 22, 2014 | 2012 Chevrolet Cruze LS Sedan 1.8L 4-cyl....

1 Answer

Lights pulsating on2004 megane scenic 1.5 dci

Sounds to be a bad ground wire feeding these light sources.

Nov 14, 2013 | 2004 Renault 181

1 Answer

My instrument lights and headlights pulsate especially when driving

I would say no to reg or alt ,when you apply brakes there is dimming and that sounds like a negitive grounding problem not at battery,the dimming is caused from a back feed of ground possible.there are what are called body ground straps from battery to body panels and far as bat or alt advanced auto and most auto parts stores will be glad to check them out for FREE ,good luck

Sep 13, 2012 | 2001 Mitsubishi Montero

1 Answer

Clutch when disengaged pulsates an sometimes does it a low rpm

This is caused by the pressure. There are tongs that are on it in a circle. They are spring loaded. When one or some are weak or a spring has broken you will get a pulsating feeling in the pedal

Sep 07, 2011 | Chevrolet G10 Cars & Trucks

1 Answer

My 2004 Neons electical system pulsates. Headlights, dash lights, etc all go slightly from bright to dim. Occasionally all the gauges will flutter rapidly. Seems to idle too low at stop lights 5-600 rpm)...

hi it sounds like it could be your alternator i think you call them generators in the US, try testing it with a volt meter, connect it to the battery and start car, if it puts out 13 to 13.5 volts on idle and 14 to 14.5 volts when you rev the engine it is ok, anything under that or even over that meens that it is faulty hope that helps

Feb 13, 2010 | 2004 Dodge Neon

1 Answer

I have A 1993 gmc jimmy,It has A rough idle,idels low,& the rpm seems to pulsate.The service light cam on I ran it & came up with code # 32.what would cause this.

this is related to the egr system and makes sense when you describe a rough idle. the egr is probably stck open slightly. remove and attempt to clean with carburretor cleaner. it also helps to have a vacuum pump so you can work the diaphragm up and down. happy holidays

Dec 28, 2009 | 1993 GMC Jimmy

1 Answer

1999 honda passport (isuzu rodeo), problem: All lights (dash,dome,headlights,....) pulsate dim bright, dim bright. Had altanator checked was ok. removed battery terminals while running and didnot die....

I have the same car and the same problems. I think it may be a ground issue. Once the weather is a bit warmer, I will be checking the different connections. Does anyone else have any ideas.

Dec 27, 2009 | 1999 Isuzu Rodeo

1 Answer

Interior & Trunck lights NOT working & headlights pulsate

Check grounds near battery.. you have a short it seems. There are also fuses in engine compartment as well.

Jul 07, 2009 | 1997 Oldsmobile Achieva

1 Answer

Pulsating or flickering lights

your car is in denial.... Have your battery load testest. If it has any plate issues it can mislead the alternator regarding its state of charge abd, by all means make sure your battery cables are clean and tight. good luck

Jun 08, 2009 | 1999 Chevrolet Monte Carlo

1 Answer

Passat problem

The climate control issue is most likely the air temperture blend door motor has quit working or the ac is low on Freon from a leak, also the control head can cause this problem, the vibration may be from hard engine mounts, when the rubber in the mounts ages it gets hard and does not absorb vibration as well, the pulsation is a low voltage issue and you should have the alternator tested.

Oct 08, 2008 | 2003 Volkswagen Passat

Not finding what you are looking for?
2005 Ford F-150 Logo

131 people viewed this question

Ask a Question

Usually answered in minutes!

Top Ford Experts


Level 3 Expert

79123 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers


Level 3 Expert

5677 Answers

Are you a Ford Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides