upshift light vacuum switch

tfs2121 · Post by **tfs2121** » Mon May 07, 2007 2:40 pm

i posted this at FEP... no responce so maybe one of you guys can help me out
does anyone know the location or have a pic of the vacuum switch used to turn on the upshift light when vacuum drops below 3 in.

looks like ford calls it an electric PVS switch

thanks for any help
or does anyone know where i can get a new one?

n20capri · Post by **n20capri** » Mon May 07, 2007 3:15 pm

I thought the upshift lights were only for 4-cyl Turbo cars?!?!?!?! I don't think I've ever seen one on a V8 car...

Post by **negusm** » Mon May 07, 2007 3:49 pm

n20capri wrote:I thought the upshift lights were only for 4-cyl Turbo cars?!?!?!?! I don't think I've ever seen one on a V8 car...

My 85 has it.

The upshift indicator on the dash is supposed to be controled by a little grey box marked something like "Grey Box" (not kidding).

I do not know (and absolutely in no way care to know) exactly how it works. I yanked the bulb from the dash for the indicator in my car. I still have the box and it is hooked up but I don't think it ever worked even before I yanked the bulb...just in case it ever decided to heal itself.

-Mike

svt1996cobra · Post by **svt1996cobra** » Mon May 07, 2007 5:46 pm

The one in my GPIV still works, I like it! I have a dash out of a 85 5.0 I will see if I can get a picture of the box for you!

David

tfs2121 · Post by **tfs2121** » Mon May 07, 2007 7:06 pm

i know what the box looks like but there is a switch that closes the circut to turn on the bulb when the motor is loaded... thats why its a vacuum switch it comes on bellow 3 inches of vacuum. it should be in the engine compartment but there are so many vacuum switches i dont know whitch one it is are they all the same?

svo413 · Post by **svo413** » Mon May 07, 2007 11:23 pm

That is a tough one. The EVTM lists it but doesn't have a picture, just a schematic. Looks like it is on the fender well possibly. It is a 2 round pin connector in natural color. One pink wire and the other pink with a black stripe. Round connector, 2 clips (at 9 and 3) and a keying notch (at 4 o-clock). I found it in the big schematics.

tfs2121 · Post by **tfs2121** » Tue May 08, 2007 1:31 pm

thank you that should help

tfs2121 · Post by **tfs2121** » Wed May 09, 2007 2:23 pm

well looks like the fire got mine. all i have left are 2 switches that i think are for the high altatude BS. so anyone looking to sell there upshift light vacuum switch? mike you said you didnt want yours are you intrested?

Post by **negusm** » Wed May 09, 2007 2:43 pm

tfs2121 wrote:well looks like the fire got mine. all i have left are 2 switches that i think are for the high altatude BS. so anyone looking to sell there upshift light vacuum switch? mike you said you didnt want yours are you intrested?

Not really. I am keeping it all on the car and will be hooking it up. I just have absolutely no intention in running down any problems with it.

-Mike

stangmodifier · Post by **stangmodifier** » Wed May 09, 2007 4:05 pm

I did not realize that light was vacuum controlled. When I first got 85 Coupe 607846 the transmission screamed at me the whole 4 1/2 hour trip from Oklahoma to Kansas. The next day I pulled the trans and replaced it with a trans from an 89 5.0 Mustang. The swap was straight forward as both trannys were obviously very similar. There was however a sensor or something that was just a little different and I had to cut and splice the 2 wires from it to the 2 wires in the car. Anyways, now I only get the shift light when I depress the clutch pedal, each and every time but only when the car is running. My thinking was that I just had those two wires reversed and that if I reversed them the light would come on to indicate the need to shift. I never switched them back cause I don't want that light telling me I'm holding a gear too long. A vacuum control????

stangmodifier · Post by **stangmodifier** » Wed May 09, 2007 4:08 pm

I even had someone ride along with me once who commented on how perfectly I timed my shifts with the upshift light not knowing I was triggering that light with the clutch pedal.

tfs2121 · Post by **tfs2121** » Wed May 09, 2007 5:12 pm

sounds like you have some stuff messed up
to make the shift light come on you must have a few things going on
1 RPM must be above 1900 should be a tach signal wire going to the gray box
2 engine vacuum must be below 3 in of merc
3 the top gear switch opens (to keep light from coming on) when in 5th gear closed in all other gears

sounds like you have some wires mixed up
i think your new trans would not have a place to plug in the top gear switch
thats what i would start with

ascMcLaren Enthusiasts

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