Right... irritating, I know... I just asked the others about that since I ran into the exact same thing.

FWIW they want us to abandon the old Gallery and migrate to/use the new Albums, but IIRC the old Gallery product is supposed to still be available IIRC.

Will letchya know when I hear back....

BTW I think Ralph (81-F-150-Explorer) posted the schematic at one time (IIRC there were two different variants) but that was years ago... good luck finding that....

 

I sent Gary a copy and if anybody else needs a copy, PM me a email address and I'll attach it over.

New photo Albums? Where is it located at? I like to keep photos I use here on FTE as sometimes the outside photo album web sites will delete the photos that are linked here if the user shuts down their account..

 

Here's the schematic - thanks, Eddie. This may well be very useful to me since I can scope it and see if there's a reasonable square wave I can feed to my AEM wideband AFR meter. No, not that I'd tap into the tach, but I might build another circuit like that. Thanks!

 

Alright everyone, please excuse my absence as I had become super busy, being active duty military is demanding at times.

I have had a couple issues with the truck since my last post. I have evil electrical gremlins. I had to fix the major connection from the alternator to the voltage regulator and starter solenoid. I replaced the voltage regulator with a digital one from rock auto, and finally got the truck to stay at 14.5-6 volts at idle, but under full load, blower on high, radio on, blinker on, headlights on, the voltage drops to 12.7-13 volts. Anyways as I was fixing this problem the tach came back to life! I couldn't believe it, although it was doing something it was not before. At first the tach was reading 400rpm with it normally reads 700-800rpms at idle, but the strange part was when i was driving going 55-60 it would only reach 2000rpm, then I went on a bumpy road and the tach all of the sudden came to life and was reading correctly! With this being taken into consideration, alongside with my fuel gauge being off by about 1/4 tank and temp gauge being on the N to O when the truck is warmed up to operating temperature I am starting to believe that my instrument panel is not receiving the correct input voltage. Therefore I would believe that since the input voltage may be so low, the tach does not want to click on at times.

So now the question is, where does my instrument panel get its input voltage from? Does it have to do with the ignition switch under the dash or ignition switch with the key? I have tried the wiggling of the key to change possibly, but to no avail. Like, what connection could possibly be loose that causes my instrument panel to get power but not enough, but at times gets enough when i go on a bumpy road...

Thank you for your time guys.

 

hi golden f100,im a new member on this site and ive been reading your problem about your loss of voltage to your instrument panel.now im no expert by no means,and maybe someone can correct me if im wrong,but have you checked the connection between the printed circuit board and the little voltage regulator on the back of your instrument panel? this little regulator I believe controls the voltage supplied to all your gauges including your tach,it could have a poor connection or the regulator could be faulty itself,ive seen these regulators cause mischief in the past,may or may not be the trouble but worth checking out

 

The IVR(instrument voltage regulator) only powers the oil, temp and fuel gauges. The tach gets the 12V power from the ignition switch. The IVR is also feed off of the same power feed and cluster grounds too.

I guessing a bad ground is occurring from the cluster to cab and then on to the chassis..

 

exactly correct,thanks for correcting me on that haha,could it possibly be an engine to body ground?

 

Very well could be any ground from cab to chassis is bad.

On my 84 F250 I am rebuilding the wire harness in the dash and engine bay. When I stripped the old harness, I found some of the "welded"(not soldered) wires falling apart inside the harness. I since used solder to fix those stupid weld joints. Hopefully my electrical gremlins will be gone.

 

well I hope everything works out good for you,i had trouble with the start circuit in my 85 f250 when I put the cummins in it,every now and then,i would go somewhere and shut the truck off,then when I would go to start the truck,it would just click the solenoid and not roll over at all,after fighting with every ground wire and battery cables and even testing starters,i finally found the problem in the red/blue wire going into the key switch,the insulator looked as new,but when I cut it off,it was completely green inside,so I replaced it out past the firewall and worked great ever since

 

Alright, lots of information, let me try to interpret. where is the the instrument voltage regulator (IVR) located? Ive taken the dash apart so many times I do not know what I am looking for.

Which ignition switch were you referring to? The one in the key cylinder or the switch on the column?

Secondly, from the stint of messages regarding grounds, what I am getting from that is...



Correct me if I am wrong. haha
Where would be a good spot to ground the cab to the chassis? Engine to chassis is straightforward enough.

 

Several things. First, grounds. On V8's there is supposed to be a ground from either the rear of the intake manifold or the valve cover to the firewall - usually around the wiper motor. And, there is a ground from the middleish of the dash to the firewall.

For the IVR or ICVR (Ford calls it both), try this link on how to make a replacement. The original device is an absolutely AWFUL design and the replacement shown will make the gauges much more reliable.

As for the ignition switch, there are no wires to the part the key goes in. It is just a lock that pulls a rod to control the switch that sits low on the steering column. And here's the wiring diagram for the ignition as well as the ICVR & gauges.

 

 

Great job, Chris!

 

I am on the third factory tach on my 86 F150 in the last 20 years. Been through the same trials you have been through with trying to fix the tach, clean it etc, and finally just got a used one that worked fine. I have a background in Computer Engineering, and spent many hours troubleshooting this tach years ago. I used to know that schematic by heart. ;-) I did have one with a bad capacitor that was acting funny, but that one went crazy eventually too.

The worst one would go really high in the RPMs for no reason. Or, on hot days, sitting in traffic, it would bounce from idle to way past 6000. Was kind of funny actually.

Have you tried another tach?

 

I have not tried another tach, as I have been unable to find one in the junkyards out here in NC, let alone one from a 1980.

I have yet also to take the dash apart again because I have been busy at work this past week.

However, I just wanted to let you guys know that the tach still comes and goes, but recently I have been getting the tach to "click" on after the truck is running by hitting the starter when the truck is already on and in a flash the tach is on. REALLY strange and I am starting to think it may be my ignition switch, yet it does not work all the time...

I do not know if that information may help but its something else related to it.