water temp gauge and tach

[mikey531]

Hi

I just put in a 383 and I am slowly getting everything working I have not been able to get my temp gauge to work. I have replaced the temp sending unit, checked the wire and still nothing. I was going to add a ground to my dash but not sure where to go. My tach did work but doesn't now. I checked continuity from the white wire at the dist and was ok. I tried the same thing with the 2 pink wires and got nothing. Can anyone please tell me what I am doing wrong? Thanks !!

[Andy4639]

On the tach the red wire goes to a fuse block spot that is hot when the truck is running. The coil wire goes to the coil ground side. I put a 5amp fuse in line on the hot red wire. If your running a HEI the tach wire is marked on the cap. Make sure it's got the connector inside the cap.

As for the temperature the green wire in the harness is the wire you need to trace out for the sender. The picture I posted shows the connector for the dash and the sender.
To ground the cluster use any one of the screws in it that goes to metal of the cluster.

[mikey531]

The old gauge worked with the sending unit in my engine now, but it didn't work so I bought a new gauge and the new one has the resistor my old one didn't I have a green wire that does not go through the connector but directly to the gauge.

I am running HEI and I checked the continuity from the white dist to the spade connector in the dash and had continuity, the two pink ones which are together did not have continuity. The tach did work but then just stopped. I was thinking a broken wire?

Thanks Mike

[Andy4639]

Mike

the two pink ones which are together did not have continuity.

What are you talking about? There is only one red wire going to the tach not 2.
There are 2 wires total. One is hot and the other goes to the Dizzy cap.

[pjmoreland]

Tach installation instructions

[mikey531]

I am using HEI ignition. I have a white wire hooked to tach on the dist. and two pinkish wires hooked to the terminal beside it.

[pjmoreland]

Do you have the two pink wires plugged into the "IGN UNFUSED" terminal on the fuse panel?

[mikey531]

I will have to go look

[mikey531]

Originally Posted by Andy4639

On the tach the red wire goes to a fuse block spot that is hot when the truck is running. The coil wire goes to the coil ground side. I put a 5amp fuse in line on the hot red wire. If your running a HEI the tach wire is marked on the cap. Make sure it's got the connector inside the cap.

As for the temperature the green wire in the harness is the wire you need to trace out for the sender. The picture I posted shows the connector for the dash and the sender.
To ground the cluster use any one of the screws in it that goes to metal of the cluster.

Do I hook a separate wire for 12 volts or does it pick it up from the cluster? I assume I run the sending unit green wire directly to the gauge?

Thanks

[mikey531]

Originally Posted by pjmoreland

Do you have the two pink wires plugged into the "IGN UNFUSED" terminal on the fuse panel?

The pink or red wire comes from the distributor ?

[pjmoreland]

Originally Posted by mikey531

The pink or red wire comes from the distributor ?

Looking at the photos you posted, it looks like the pink wires go to the 12V terminal on your tach. The wires that go to that 12V tach terminal should be routed to the "IGN UNFUSED" fuse panel terminal. The other wire (white wire) should go to your HEI.

[mikey531]

Ok thanks do you know about the temp gauge? Thanks

[pjmoreland]

Originally Posted by mikey531

Ok thanks do you know about the temp gauge? Thanks

If your old temp gauge had a wire running straight to it, then it sounds like a previous owner did some custom wiring on it. Normally the signal is routed through the flexible printed circuit board to the green wire Andy mentioned. This green wire then makes its way though the firewall bulkhead connector and then to your sender. You might want to start with checking for continuity from the sender connector to the temp gauge terminal, as shown in Andy's post. And, as already mentioned, the problems you are having with both of your gauges could very well be a result of inadequate grounding. There is a black ground wire in the under-dash harness that is supposed to be clipped to the metal dash. This also assumes you have a ground strap running from your firewall to the engine.

[Andy4639]

Per your picture:

Color of wires doesn't matter as long as you hook them up right to complete the circuit.
The white wire should go to the coil terminal on the tach and tach terminal on Dizzy cap. The red wires in your picture should go to the unfused terminal in the fuse block. The second red wire not sure about because it's not suppose to be there. I would cut it off are tape it off. The other picture is my factory tach speed warning cluster showing you the tach only has 2 wires.

As far as the temp gauge goes it gets it power from the cluster plug in. The sending unit grounds it so it reads.
Did you use teflon tape to mount the sending unit? If you did it may not be making contact to ground it.

[Andy4639]

If these connectors are the other end of the tack harness and you hooked them up to the dizzy cap you more than likely burnt the tach up. Most HEI caps are marked tach and 12 volts.




Here is the HEI marked up. bottom 2 connections are what you need to look at.

[mikey531]

I did hook the tach up correct as it did work for awhile. I checked the continuity on t he white wire and it was ok. I have not checked the red wire yet to see if has power. I will do that tomorrow. I did not use teflon tape. I did put in the temp gauge and tried the sensor wire and nothing it didn't even move. I am getting ignition 12 volts on at the dist but didn't check under the dash. I need to get a plug for my oil pressure gauge so I can start the truck. I will let you know. I did run two more ground in straps on the cluster. The cab and frame are grounded to the engine. Thanks for the help.

[Andy4639]

Does the truck run? That second RED,PINK wire does it have a separate connector on the other end are they together like the tach side?

[mikey531]

They are together and hook into the 12v side of the tach. I unhooked the second wire and the choke stopped working so it does feed the choke not sure what else yet

[Andy4639]

Originally Posted by mikey531

They are together and hook into the 12v side of the tach. I unhooked the second wire and the choke stopped working so it does feed the choke not sure what else yet

That's what I meant was it feeding something else off the tach. I wouldn't have anything coming off that wire at all. Just for insurance. If it back feeds it would take the tach out. I would find another place to hook it up.

[mikey531]

So all I need is one wire for power to the tach? I assume I could use a new wire from the dist to the tach but is has to get power from somewhere? The power to the tach is what feed the distributor correct? So I could pick up power anywhere for the tach as long as I have the tach wire hooked up?

[Andy4639]

Yes the tach power should come from the fuse block like we stated earlier.

[mikey531]

Thanks Now any ideas on how to get my temp gauge working? I have a new wire going from the gauge to the sending unit, I have tried two sending units and two gauges and grounded the dash cluster. In my first post where does the sending unit hook up?

[pjmoreland]

The wire from the temp sending unit connects to the gauge post closest to the steering column, as shown in Andy's previous post. You should have 12V on post farthest from the column when the ignition is on. It would be good to verify with a voltmeter.

[mikey531]

Thanks