high beam indicator will not come on, failing state inspection
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MustangLX-5.0
Founding Member
Did you use the correct bulb? They can be difficult to find as they aren't very common.Try switching with a bulb from another indicator that isn't used (such as the OD light if you have a manual trans. or low oil light).Most of those bulbs are the same type except for the gauge illumination.Another thing you could check is the wiring harness plugs that plug into both sides of the gauge cluster.Make sure they are fully inserted and locked in.unplug and replug in just to be sure.If that is not the problem,then it may be in the signal switch or the wiring to it.You'll have to remove the steering wheel collar.This is the plastic cover that goes all around the neck.There are a few screws that hold it together noted by the holes at the bottom.One of the holes is not a screw (ignition lock release ..).You'll also have to remove the knee bolster and the cover behind it in order to fully remove the collar.The bolster cover is just below the steering column.Once you get the collar off,check the wiring to the signal switch.Make sure it's plugged in fully and not loose.Turn brights on and wiggle wires a little.See if HB indicator lights up.If that still does not fix it then you may have a faulty switch.
i swapped out the bulb with another known good bulb with no change, the high beam indicator even work in another place(the ABS spot). i had a known intermittent problem with the blinker/wiper switch where the wipers stopped working while the blinker were on and i thought it might not be telling the high beam bulb to light when the brights are on. i replaced the blinker/wiper switch and the intermittent problem went away. but the HB indicator problem still exists. i am sure that the connections on the gauge cluster and wiper/blinker switch are connected all of the way. by the way, thanks for the reply. i'm totall stumped here. do you think the gauge cluster might be bad?
MustangLX-5.0
Founding Member
What year is your mustang? Is the odometer mechanical or a digital readout?
I have two gauge clusters.One from my 96,and one from a 95 GT.Following the pcb trace on the back (where the bulb plugs in),the trace goes straight from the bulb to the left harness connector (side nearest the headlamp switch).It's a very small trace and doesn't pass through any other circuit before the harness.Unless the trace is damaged somehow,the problem isn't in the cluster.When you swapped bulbs,did you remove the bulb from the plug itself,or did you swap the entire plug with bulb in place? It you removed the bulb,I would swap the entire plug as there could be a contact problem inside the bulb socket.Check the trace where the bulb plug twists into place.Make sure those pins on the plug are contacting the copper trace.Make sure the trace isn't torn.
Since you already replaced the switch,I am starting to get a bit stumped myself.Aside of checking what I just suggested above.Check that,and I will look into the wiring between the cluster and switch.
I have two gauge clusters.One from my 96,and one from a 95 GT.Following the pcb trace on the back (where the bulb plugs in),the trace goes straight from the bulb to the left harness connector (side nearest the headlamp switch).It's a very small trace and doesn't pass through any other circuit before the harness.Unless the trace is damaged somehow,the problem isn't in the cluster.When you swapped bulbs,did you remove the bulb from the plug itself,or did you swap the entire plug with bulb in place? It you removed the bulb,I would swap the entire plug as there could be a contact problem inside the bulb socket.Check the trace where the bulb plug twists into place.Make sure those pins on the plug are contacting the copper trace.Make sure the trace isn't torn.
Since you already replaced the switch,I am starting to get a bit stumped myself.Aside of checking what I just suggested above.Check that,and I will look into the wiring between the cluster and switch.
MustangLX-5.0
Founding Member
Do you have Daytime Running lamps? I mean,does your headlights turn on in the day or is there some other switch or control on the signal switch or headlamp knob that has an "auto" function to it? If you are not sure,check.This will change everything if you do have DRL.
Other than DRL,if you don't have it,the HB indicator is directly tied into the bulbs.It's on the same hot wire as the hb bulbs are.The wiring shows the HB switch & Flash to Pass,B+ output to HB bulbs and parallel with the HB indicator bulb (just making sure you get what I'm saying).If you have DRL,it comes from the switch and then to the headlamps,but parallel to the DRL module.It then comes from another connection on the DRL module to the HB indicator.Thee DRL module would control it.
Other than DRL,if you don't have it,the HB indicator is directly tied into the bulbs.It's on the same hot wire as the hb bulbs are.The wiring shows the HB switch & Flash to Pass,B+ output to HB bulbs and parallel with the HB indicator bulb (just making sure you get what I'm saying).If you have DRL,it comes from the switch and then to the headlamps,but parallel to the DRL module.It then comes from another connection on the DRL module to the HB indicator.Thee DRL module would control it.
i dont have DRL. here's something i tried, maybe you can tell me if this would be a legit check.
i traced the conductor from where the bulb plugs in to where the connector on the back of the instrument cluster goes. i found that the connector has a gray and white cable thats associated with the high beam indicator. how can we find out how much power should on the connectors pin when i have the lights on and turn on the high beams? ive been looking at a diagram i found on the internet but i guess i dont really know how to use it very well. here's a link to the diagram i'm talking about. once again thanks for you help.
Ford Forums
i traced the conductor from where the bulb plugs in to where the connector on the back of the instrument cluster goes. i found that the connector has a gray and white cable thats associated with the high beam indicator. how can we find out how much power should on the connectors pin when i have the lights on and turn on the high beams? ive been looking at a diagram i found on the internet but i guess i dont really know how to use it very well. here's a link to the diagram i'm talking about. once again thanks for you help.
Ford Forums
Skymarshal
Member
If none of your troubleshooting works, you might be forced to run a new circuit. I've had to do that before when every attempt to locate a problem fails. It wouldn't be too hard to pull both the power and ground off one of the high beam sockets and run it back to the cluster, using a smaller bulb that is insulated from the pcb. Make sure the wire is protected from chafing and heat and use a low wattage bulb and it will last forever!
MustangLX-5.0
Founding Member
He was suggesting you splice into the wiring for the high beams,at the bulbs.I thought instead of running wire from the bulb socket,run it from the high beam wiring direct from the signal switch.You know for a fact that the high beam headlights are getting power,both on high and on flash to pass.So the actual fault lies between the switch and the HB indicator in the gauge cluster.
I would run a couple more tests just for the heck of it before you start running wires all over.You have a volt/ohm meter...right? Ok,now disconnect the two wire harness plugs on the back of the gauge cluster.Disconnect the HB socket from the board.Now turn your meter on resistance (ohmmeter setting,looks like an upside down horseshoe).Now,looking at the reverse side of the board with the HB socket on the top,put one probe on the contact that the bulb socket would normally connect to.Probe the lower contact that traces down and to the right which ends where the harness would plug in.Now put the other probe where the trace ends at the harness.Make sure the probe touches the exposed copper trace on the plastic strip.The meter should read 0 ohms when both probes are in the correct spot.If it shows "out of range" or some sort of infinity symbol or even nothing at all then move the brobes around to make sure your getting a good connection.The meter should not read higher than 0.1 ohm.If it does then you have a connection problem.Clean the contact area on the board with isopropal alcohol (clear rubbing alcohol 70 - 90% ).The other trace on the top of the bulb socket is ground.You'll notice that many other traces connect with that one.
The other and last test you can try.
Where the harness plugs into the gauge cluster,probe the pin (On the harness plug) that connects to the HB.You can do this two ways.You can set the meter to (DC volts ) setting.This setting may show 2 lines,one that is dashed or broken,aand the other a solid line (thats DC Volts).Make sure you set it to a range that reads up to 14 V.Now,with the one probe on the plug,turn your headlights on and switch to high beams.Connect the other probe to a good grounding source such as bare steel with a ground tied to it.The meter should read 11 - 14 volts with the HB turned on.If it doesn't then theere is a fault in the wiring going to that plug.The other method I mentioned was to use either ohmmeter or continuity and probe from that plug ..and connect the other probe to the correct pin on the plug that is connected to the signal switch.Doing it this way just checks for a break in the wiring between the switch and cluster.You leave the headlamps off (no power).Use the continuity setting for this.That way it will give you an audible beeeeep whenever the connection between the two probes is complete.When ever you remove the probes or there is a bad connection somewhere,you wont hear the beep.This helps you trace broken wiring easily without having to constantly look at the meter.
I would run a couple more tests just for the heck of it before you start running wires all over.You have a volt/ohm meter...right? Ok,now disconnect the two wire harness plugs on the back of the gauge cluster.Disconnect the HB socket from the board.Now turn your meter on resistance (ohmmeter setting,looks like an upside down horseshoe).Now,looking at the reverse side of the board with the HB socket on the top,put one probe on the contact that the bulb socket would normally connect to.Probe the lower contact that traces down and to the right which ends where the harness would plug in.Now put the other probe where the trace ends at the harness.Make sure the probe touches the exposed copper trace on the plastic strip.The meter should read 0 ohms when both probes are in the correct spot.If it shows "out of range" or some sort of infinity symbol or even nothing at all then move the brobes around to make sure your getting a good connection.The meter should not read higher than 0.1 ohm.If it does then you have a connection problem.Clean the contact area on the board with isopropal alcohol (clear rubbing alcohol 70 - 90% ).The other trace on the top of the bulb socket is ground.You'll notice that many other traces connect with that one.
The other and last test you can try.
Where the harness plugs into the gauge cluster,probe the pin (On the harness plug) that connects to the HB.You can do this two ways.You can set the meter to (DC volts ) setting.This setting may show 2 lines,one that is dashed or broken,aand the other a solid line (thats DC Volts).Make sure you set it to a range that reads up to 14 V.Now,with the one probe on the plug,turn your headlights on and switch to high beams.Connect the other probe to a good grounding source such as bare steel with a ground tied to it.The meter should read 11 - 14 volts with the HB turned on.If it doesn't then theere is a fault in the wiring going to that plug.The other method I mentioned was to use either ohmmeter or continuity and probe from that plug ..and connect the other probe to the correct pin on the plug that is connected to the signal switch.Doing it this way just checks for a break in the wiring between the switch and cluster.You leave the headlamps off (no power).Use the continuity setting for this.That way it will give you an audible beeeeep whenever the connection between the two probes is complete.When ever you remove the probes or there is a bad connection somewhere,you wont hear the beep.This helps you trace broken wiring easily without having to constantly look at the meter.
MustangLX-5.0
Founding Member
oh and I cant see the diagram on that link.You have to have an account there to be able to view it........ 
ok, heres what i did. i checked the power that should be coming through the gry/wht wire when the brights are on and there was only millivolts present when it should have been about 12 volts. another thing i did was check continuity from the gry/wht wire to the black wire while it was connected to the cluster. continuity was good, so in my mind it seems like the instrument cluster should be good it atleast has the ability for power to come in to the indicator and send it back to ground. i also check continuity from the indicator plug to where the wire harness connects and that was also good. i'm not sure how to check continuity from the instrument cluster wire harness to the multifunction switch because there is no gry/wht wire coming out of the multifunction switch. man i'm lost.......
if i check continuity from the gry/wht wire to the grn/blk wire would that be a legit check?
if i check continuity from the gry/wht wire to the grn/blk wire would that be a legit check?
MustangLX-5.0
Founding Member
Continuity from grey/wht to black wire..I'm assuming you were checking to make sure bulb returned a good connecion.That works and that's also good as it rules out your cluster and bulb socket.
Check continuity from grey/wht to Lt green/black.The light green/black wire is the other side of the grey/white wire on the switch.So yes,it would be valid to check.Millivolts from the gry/wht wire,are you sure you had a good ground and that also you had the meter on the correct setting? Just making sure.If that's the correct reading then there is definately a problem in thw wiring between the switch and cluster.It may be a loose wire at the switch,or or even pinched or corroded wire at the terminal.
Check continuity from grey/wht to Lt green/black.The light green/black wire is the other side of the grey/white wire on the switch.So yes,it would be valid to check.Millivolts from the gry/wht wire,are you sure you had a good ground and that also you had the meter on the correct setting? Just making sure.If that's the correct reading then there is definately a problem in thw wiring between the switch and cluster.It may be a loose wire at the switch,or or even pinched or corroded wire at the terminal.
the meter was definitely on the right setting but i'll try again for the heck of it. i was grounding to metal that was behind the cluster but i'll try another known ground in the engine bay just in case. i'll check between the gry/wht wire and the LT grn/blk wire today when my wife gets home with the car. are there any detail diagrams that we can get out hands on? thanks again for all the help, i'll let you know what happens after i check.
MustangLX-5.0
Founding Member
I'd have to look around for highly detailed diagrams.In the meantime,try a Haynes manual for 94-04 Mustang.Has decent diagrams in the back on the manual for every section of the vehicle.$10 - $15 at Advanced Auto Parts.There's also Chiltons,but I'm not sure on how detaled their wirng diagrams are.Only bought Haynes the last 10 years.
Just curious,but what sort of inspection is this? I can see having to pass emmisions test and even exterior lamps,but a dash light??? What state do you live in?
Just curious,but what sort of inspection is this? I can see having to pass emmisions test and even exterior lamps,but a dash light??? What state do you live in?
well i dont know what is causing the problem but i found a solution. i found a inspection shop that is letting me just put a bulb that will light up blue in the dash board when i turn on the brights. i just connected one lead of the bulb to ground and the other lead to the green/black wire coming out of the multifunction switch. the fact that a bulb will work this way and not in the instrument cluster is weird so i also bought a cluster from a junk yard that worked great besides the HB indicator not lighting. still dont know what caused the problem but at least i'll be able to get the car inspected now. i'm pretty much just gonna take the installed bulb out after inspection. thanks for everyones help. i might be back later if anything else goes wrong........i'm thinking there probably is some problem somewhere that could eventually couse more problems.......
oh yeah, i already got a haynes manual and the drawing doesnt get too specific.......at least not with pins and power. i live in virginia and they are like Notzi's on inspections, i even looked on the DMV website at what they inspect and sure enough the HB indicator is on the list.
once again, everyone has been a huge help!!!
oh yeah, i already got a haynes manual and the drawing doesnt get too specific.......at least not with pins and power. i live in virginia and they are like Notzi's on inspections, i even looked on the DMV website at what they inspect and sure enough the HB indicator is on the list.
once again, everyone has been a huge help!!!
MustangLX-5.0
Founding Member
I'm going to look on my 96 and see what lies in between the switch and cluster.There's only about 2 - 3 feet length of wire between the two.I'm sure there's a coupler in between the two.Would have to be since each end of the wire is a totally different color.It's probably where the two merge.I'll let you know what I find out.In the meantime,good luck with the inspection.
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