i have a 1981 ford truck that did not come with factory tach

i found a truck dash assembley with the tach in it and now i dont know how to hook it up has any body else had this problem does any body know where the wires go on the tack for the coil ,ground.\, lights,and key power

 

If you have the entire dash assembly w/ tach, just swap it in, its direct plug & play if you have factory full gauges in your current cluster.

It should be direct plug & play. IF your truck has idiot lights, then, i'm not sure.

Good Luck!

 

You don't have to do anything, all ford trucks are already wired for the tach option and you just unplug your old one and put in a new one....... If you get the right one.

I say this and came here for help because i too just did this. Everything works great EXCEPT, the circuit is different for my right turn blinker and my E-Brake light. Now ehn I turn on my right blinker, my Brake warning light blinks and when I set the E-brake, my right turn gauge indicator comes on.

I tried playing around with swapping pins around and it doesn't work because the E-brake light is constant hot and uses a ground to turn it on, the turn indicator is supposed to be on shared ground and then has the 12 VDC hot signal when the blinker is on.

Other than cutting the lights off the dash and swapping places, anyone know what went wrong? Do I have a wrong year gauge cluster?

My truck is an 86 F-150 XLT with automatic Tranny and the 4 gauge cluster originally without the tach but now with it.

One added bit of info I figured out when I tried swapping the pins 4th from teh left for teh turn signal and 6th from the left which was the constant hot for the E-brake light, ( which didn't work unless I put on teh E-brake one click to get a ground for the turn light). The Constant hot E-brake also feeds the tach so when I swapped pins, the Tach dies unless. I can make it start-stop this way by turning on the turn signal. In other words, the circuit board is wired so that the E-brake is constant hot and shares this to power the tach on the new gauge cluster I picked up. On my original without tach dash, there was no tach to power so the E-brake circuit is on it's own and is a direct hard wire feed from the 5th and 6 th pins from the left with 5 being ground and 6 constant hot.

I guess I could cut off the circuit board in the corner and then solder in my old one adding a jumper to power the tach but I thought if someone knew what went wrong, I might be able to go back and swap this one out for a different cluster. The new cluster was stamped EA88 which had me wondering if it was a 1988 cluster instead of a 80-86 cluster but I found a few pictures of 87 and 88 clusters and those had round gauges and looked nothing like ours.

Any help would be appreciated.

Also, what is normal tach readings for your trucks? It seemed to be reading lower than I expected. Idle reasonable at 700 or so but then cruising at 70 it said i was only doing 2000 RPMs. I have AOD and might be geared low but it still sounds low to me.

When I get more time, I will tach it with my shop gauge and compare but for now, I was just curious. The new temp gauge reads a bit lower as well so I will have to get out my temp meter and see what the tempo is at normal driving and then with the A/C on and idling. My old gauge made it appear I was about to over heat if I let it idle with the A/C on too long but this one barely budged off of "normal low end".

Good Luck,

Lee
http://www.marketswing.com/forum

 

'86 should have been a "plug and play" If you have a V8 you need to ground the black wire in the harness - if you have the 300 no ground is needed.

 

Yep, I keep reading it should be plug and play but this one is definitely not. I contacted the seller and he stated it came off of a 1980 truck. According to my Haynes manual, the 1980 is wired different so I guess from now on I know I need a 1981 through 1986 and not an 80-86.


I am trying to pick up another one but if not, I guess I can solder jumper wires to the IC board or put my old one back in.

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I should post this somewhere else but since I am here.......

I have the chance to buy a 4x4 same year truck dirt cheap. I have been looking for a donor truck for months so I can do the 4x4 conversion to my 2WD. I have read here many times that I should try to match transmissions and engines as much as possible. I was going to try to do this ( I have a 302 with AOD) but this donor truck is practically free so now I am tempted to go ahead and buy it with a 460. Not sure of the tranny yet but I would assume a large block tranny isn't going to matchup to my small block and I really don't want to switch motors and pay the higher fuel bill.

I am not an off-roader and don't want to build a Monster Truck. I do hunt and need to climb a gravel hill in deep snow occassionally though so need 4WD.

I am going to look at the truck tonight but is there a remote chance that I can just swap bellhousings? How hard is it to put a short shaft on my AOD so I can use it?

The year matches, it has decent wheels wirth more than the asking price so I am really tempted to get it and then work on the headaches later and maybe even swap the axles but leave the drive train to the front disconnected until I can stumble on a short shaft C6 that will bolt up.

What did 460s generally come with for trannies? I assume a C6 and if so, how much will my milage take a hit from my AOD?

Thanks.

Lee

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PS - Braxton - Swapping that gauge set is a breeze. Shouldn't take you more than an hour. I have had mine in and out 10 times in troubleshooting my problem and can now do it in my sleep.

Phillips screw in the steering column to take that plastic shroud off so the bezel around the gauge set will clear the column. (Screw is on the bottom)

Take out the 3 top screws holding the dash bezel on and lift and pull.

4 screws hold the gauge set in.

Disconnect check engine light in upper left corner by twisting 1/4 turn

unplug speedo by bending towards the passenger side to get little nipple to let loose of groove or use small screwdriver if it is tight to pry out slightly on drivers edge. Once nipple is diengaged, it just pulls right out.

Unplug big rectangular electrical plug from back of gauge set. It is near the top just slightly passenger side of center. It has two squeeze tabs on either side. It might be a bit hard to get your hands back there but it doesn't take a whole lot of pressure if you are good at getting torque with your thumb on one side then kind of squeeze your finger in and pull the other way.

Last, pop the little holder for your automatic shift indicator to slacken up the white plactic actuator on the passenger side of the steering column. Take a 5/16 socket/nut driver and remove the screw that is holding this same cable to the column but on the drivers sisde of the column. Slip off the little copper wire from the screw tab and then twist the white lock down fitting so you can lift from the groove by the screw you pulled earlier.

Your done. Now reverse the process to put the new one in.

It took longer to write this than it takes to actually do it.

If your new sees through cover is scratched up, you can swap your old one in as there are just a few 1/4 drive screws holding the whole thing together.

Each gauge can also be swapped out if they don't read the same as your old one. Those nuts are 5/16 as I swapped my fuel gauge out due to the new one reading low.

 

What's a Tach dash worth ??

 

I paid $25 on Ebay but I have seen them go for as high as $50 there. Junk yard would probably charge more.

Good Luck,

Lee

PS - That other truck was already gone. Doh!!