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bulb question

87coug 20th

one either side of the grille, there are double element bulbs.
why are they double element?
I swapped out the oem yellow for clear.
Also added my new"er" grille and complete clear lamps up front.

I tested a few things and did not see what function made the second element light up.

bulb question

Reply #1 –
Quote from: jcassity;275175
87coug 20th

one either side of the grille, there are double element bulbs.
why are they double element?
I swapped out the oem yellow for clear.
Also added my new"er" grille and complete clear lamps up front.

I tested a few things and did not see what function made the second element light up.


If you have an 87, there are two sets of lights, one on the corner and one inboard. As designed from the factory, the outer ones double as turn signals and parking lamps while the inner ones function only as the parking lamps.

See if it is possible that you got the bulb and wiring sockets mixed up between inboard and outboard. The outboard bulbs should have dual filament sockets. If that is correct, check for 12V in the socket with the parking lamps on. Could be a bad socket not contacting the base of the bulb. It could also be bad wiring connections. Does it not light up on both sides? Another thing to check is to see if the bulb is inserted the correct way in the socket. The sides of the bulb base has pins. One is set higher than the other and is designed to only go in one way. However many times I have seen these bulbs forced to go in the wrong way in the socket.

bulb question

Reply #2 –
Quote from: Watchdevil;275186
If you have an 87, there are two sets of lights, one on the corner and one inboard. As designed from the factory, the outer ones double as turn signals and parking lamps while the inner ones function only as the parking lamps.

See if it is possible that you got the bulb and wiring sockets mixed up between inboard and outboard. The outboard bulbs should have dual filament sockets. If that is correct, check for 12V in the socket with the parking lamps on. Could be a bad socket not contacting the base of the bulb. It could also be bad wiring connections. Does it not light up on both sides? Another thing to check is to see if the bulb is inserted the correct way in the socket. The sides of the bulb base has pins. One is set higher than the other and is designed to only go in one way. However many times I have seen these bulbs forced to go in the wrong way in the socket.


Im not sure where you are going with all that.

does anyone know the answer to the question?  Im a little stumped but the evtm might tell me more.

bulb question

Reply #3 –
am i reading this right?
second filiment was never intended to be used?
I do have lamp out warning but it doesnt seem relevent.

bulb question

Reply #4 –
Both inner and outer lamps used double filament bulbs. Whichever lamp serves as your turn signal, the opposite lamp only comes with the parkinglamps... Both inner and outer lamps come on with the parking lamps.

bulb question

Reply #5 –
Quote from: Watchdevil;275190
Both inner and outer lamps used double filament bulbs. Whichever lamp serves as your turn signal, the opposite lamp only comes with the parkinglamps... Both inner and outer lamps come on with the parking lamps.


does this mean something that helps answer the question?

bulb question

Reply #6 –
Quote from: jcassity;275194
does this mean something that helps answer the question?


It should.. Ford from the factory used dual filament bulbs in both sets of lights inner and outer but they only used the dim portion of the bulb for the lamp that does not operate as a turn signal. The bright filament was not originally wired to function.

bulb question

Reply #7 –
Quote from: Watchdevil;275196
The bright filament was not originally wired to function.

well after three posts you finally stated how it's wired(or isn't in this case)...

Scott I dunno why they used a dual filament lamp for the inside lamps, T-Birds are the same... Maybe Ford wasn't trusting of the smaller size single filament lamps??? I can't remember seeing a 3057 style lamp with a single filament...

bulb question

Reply #8 –
Ford still does this. On 96-09 Mustangs the innermost rear light is park only, but it's a dual filament bulb. Ford simply didn't add the third "stop/turn" wire. As to why it was done I'm sure it's a cost cutting reason, probably cheaper to buy the 3057 style bulbs in bulk than to buy two different type bulbs
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bulb question

Reply #9 –
hey watchdevil
i have a curiosity,,,,,,,
can you verify your inner headlamps on the bird hot wire colors?

I have  a theory that occured to me last night while swapping the header panel lenses.

The theory is,,,,
The inner lighting on 4eyes were wired out because these lamps were bulb assemblies.

The inners on 87-88 were bulb housings and not capable of containing the heat disipation of both elements due to the cubic inches of space within the housing.  From an engineering perspective, ford probably decided the wattage of both elements being on exceeded the space required to light both up so they wired only the low beam.


Thunderchicken,,
i might be reading too deap into the pony comment but the inner fronts on my coug's have three conductors, 2+g.  The wire is there but prob dead end somewhere.

bulb question

Reply #10 –
Scott in the '86 EVTM, wiring is shown with the dual filament lamp with only one element connected, same as the drawing you posted...

bulb question

Reply #11 –
well, that shoots that theory down.

bulb question

Reply #12 –
It's been a while since I had my last 87, but it seemed to me that the hazard flashers made the inners light up...?

Maybe not, heh.

CoogarXR
CoogarXR : 1985 Cougar XR-7

bulb question

Reply #13 –
Quote from: CoogarXR;275247
It's been a while since I had my last 87, but it seemed to me that the hazard flashers made the inners light up...?

Maybe not, heh.

CoogarXR


Since the EVTM shows the high side as not connected, not likely...

bulb question

Reply #14 –
Quote from: TurboCoupe50;275207
well after three posts you finally stated how it's wired(or isn't in this case)...

Scott I dunno why they used a dual filament lamp for the inside lamps, T-Birds are the same... Maybe Ford wasn't trusting of the smaller size single filament lamps??? I can't remember seeing a 3057 style lamp with a single filament...


Yeah sorry it took three posts but I misunderstood when I read his first post assuming he could not get something to light up that was supposed to. The more he explained the more I realized that he was referring to the socket that only uses one filament.

Quite simply, Ford probably just found it unesssary to have to have two different type bulbs on the assembly line when one will do the job. Just like they do for the taillamps of the 96+ Mustangs where all three sections use the same bulbs but the innermost section only lights up with the running lights but not the brakes and turn signal.