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Here is a photo that might help.
Lets start with the basics first. The top three connector in the photo below are (left to right) the DS2 IGN power plug, 4 wire DS2 plug and the one on the right is the source for the tachometer. Green is the tachometer signal and black is the GRD for the "8" post on the tachometer.
You will only have this plug on the far right if your DS2 donor harness was off an 1980 or newer F150. 1979 and older donor harness don't have this connector.
Unplug the tachometer connector and hook up one of your spare instrument cluster, using jumper wires, to the engine side of this plug. Use the diagram in post 9 and connect it directly to the studs on the tachometer.
Also with the connector unplugged my gut feeling is your cruise control will still work.
I already suggested you/he try and physically trace the wires again as they are not related to the cruise control stuff at all... here's proof, scroll down to Page 67 for a diagram of the Speed Control unit (the Servo is the component under the hood; the other box is mounted on the steering column inside the cab):
I will again suggest that removing the padded dash pad makes things a LOT easier, can trace the wires from the tachometer back to the firewall.
I see what you are saying. I had to study the diagrams for a while, but I can see that you sir, are correct.
I will go to the shop tomorrow with this information and hopefully we can figure it all out.
P.S. The dash pad has been removed for a whole year now, so it's not like I didn't want to pull it.
(I would like to give you positive reps for being patient and spelling it out slowly for me, and to Gary Lewis for supplying the diagrams, but I have to "spread the love" some more.)
Here is a photo that might help.
Lets start with the basics first. The top three connector in the photo below are (left to right) the DS2 IGN power plug, 4 wire DS2 plug and the one on the right is the source for the tachometer. Green is the tachometer signal and black is the GRD for the "8" post on the tachometer.
You will only have this plug on the far right if your DS2 donor harness was off an 1980 or newer F150. 1979 and older donor harness don't have this connector.
Unplug the tachometer connector and hook up one of your spare instrument cluster, using jumper wires, to the engine side of this plug. Use the diagram in post 9 and connect it directly to the studs on the tachometer.
Also with the connector unplugged my gut feeling is your cruise control will still work.
Report back on step one.
Jim
Yes, I have that 2-plug tachometer connector in my ignition harness.
Does the male end of this plug lead directly to, and is a part of, the large connector that plugs into the back of the instrument cluster?
I see what you are saying. I had to study the diagrams for a while, but I can see that you sir, are correct.
It becomes more clear when you understand the diagrams, huh?
Originally Posted by LARIAT 85
P.S. The dash pad has been removed for a whole year now, so it's not like I didn't want to pull it.
Mine has been removed for ~10 years now, and I guess I forget that most everybody else doesn't have that access and I have a hard time understanding why people just don't crawl into there and look at the wires.
Originally Posted by LARIAT 85
(I would like to give you positive reps for being patient and spelling it out slowly for me, and to Gary Lewis for supplying the diagrams, but I have to "spread the love" some more.)
Thank you for the thoughts! That's enough... besides, you help me out here, too, so it's all good.
Originally Posted by LARIAT 85
Does the male end of this plug lead directly to, and is a part of, the large connector that plugs into the back of the instrument cluster?
The way I remember it is yes to both... but my truck is ~10 miles away in my brother's back yard and I can't go look, hafta go on memory... as I remember it, those wires are part of that large connector but I don't remember if those wires leading up to that connector are wrapped in electrical-tape-type of stuff or not... but I *think* they are, I think all wires that run through the firewall are protected like that somehow....
Do you have the rest of this page, so I can read the entire "REMOVAL AND INSTALLATION" procedure?
Sorry I don't That is just a google image search pic that I grabbed when I was trying to grasp the differences between gas and diesel tachs. Removal and installation of the gauge itself is very straight forward though if that's what you're looking for... It's just taking the lens and face plate off the cluster and then the 4 spring nuts on the back of the gauge that contact the PCB (and holds the gauge in place).
It turns out two plugs that are a part of the Duraspark harness were mixed up during re-assembly.
Under the hood, the 2-wire tach plug was erroneously connected to the cruise control plug where it leads to the cruise control amplifier inside the cab, and the cruise control plug was erroneously connected to the plug that went through the firewall to the instrument cluster. That explains why the mechanic at the shop insisted the tach wire traced directly to the cruise control amplifier, and why the tach would work (somewhat) once the vehicle got moving.
So, it seems that my original instrument cluster was connected correctly before the restoration, but build-up inside the tachometer would make it "stick" until the vehicle warmed up or the weather was hotter, like this thread described:
Then, when I replaced that cluster with a much better-looking and lower mileage instrument cluster, the plugs were erroneously reversed, causing a similar situation where the tach wouldn't work at all at idle, but would work (somewhat) once the vehicle got moving.
Then, when I replaced that cluster with a much better-looking and lower mileage instrument cluster, the plugs were erroneously reversed, causing a similar situation where the tach wouldn't work at all at idle, but would work (somewhat) once the vehicle got moving.
Thank you all for the help!
If you want to try your luck, again, you would be hard pressed to find a "much better-looking and lower mileage instrument cluster" than this:
Huh... thanks for the update, Fonz... generally, that kind of thing can't happen as there usually aren't two of the same size & shape connectors near each other for such an error to be made e.g. you can't plug the radio into the clock harness by mistake, it just won't fit. But maybe the cruise control device was an exception to that rule for some reason....
Huh... thanks for the update, Fonz... generally, that kind of thing can't happen as there usually aren't two of the same size & shape connectors near each other for such an error to be made e.g. you can't plug the radio into the clock harness by mistake, it just won't fit. But maybe the cruise control device was an exception to that rule for some reason....
I didn't take a hard look at it, but the plugs did look very similar.
Now that you mention it, the clasping tabs on two of the female "shell" connectors from the Duraspark harness have broken off. Do you know where I can get replacement connectors?
That is just a google image search pic that I grabbed when I was trying to grasp the differences between gas and diesel tachs. Removal and installation of the gauge itself is very straight forward though if that's what you're looking for... It's just taking the lens and face plate off the cluster and then the 4 spring nuts on the back of the gauge that contact the PCB (and holds the gauge in place).
