Hey everybody, just bought my first 87 Sammy! Needs a little bit of work before it's street legal and I'm fixing it up myself to learn more about mechanics. Right now, I'm trying to tackle why my temperature gauge and tachometer aren't working. The gas gauge works and I fixed the speedometer cable.

For the temperature gauge, I'm trying to determine if its a bad sending unit, wiring issue, or a bad gauge. Problem is I cant seem to figure out where exactly the sending unit is to test it... I've attached an image of where I think it is. The two units on the left look the same to me so I have no idea which one would be the sending unit and what the other one would be. I cant remember what the other arrow is pointing to on the right but Im pretty sure its not the temp sending unit. 

For the tachometer, I dont really know where to start.. any advice would be great.

Thanks for the help. Please speak to me as if I'm an idiot.. I'm fairly new to this so my mechanical knowledge isn't the best.. yet!

The three sensors in your picture appear to be oil pressure related - the top most one is where the oil pressure switch fits - the other two are non standard, and I have no idea why anyone would want to make those modifications.  As long as the oil pressure light comes on with the ignition and goes off when the engine starts, you can probably leave them as they are.  The temp gauge sensor is on the intake manifold under the thermostat outlet elbow - find the radiator top hose and follow it back to the engine - there may be just one sensor or more than one.

Go to Ack's FAQ (google it if you need to) and download the manuals & diagrams for your vehicle, find the wire color for the temp gauge and then find the gauge sensor - connect the sender wire to ground through a side lamp bulb and see if the gauge moves - use the same diagrams to verify the tach wiring.

Thanks fordem. I'll check these later tonight. It seems that a previous owner made some unusual modifications which is adding to the confusion.. haha

So I looked at it last night. I think I found the temperature sender. Is it what is shown in the picture? There's only a wire wrapped around part itself. There is no wire connector or anything. Seems like someone tried taking a shortcut. I tried grounding the wire and checking to see if the temp gauge went up when I turned on the aux power and nothing happened. If I'm correct about this being the sending unit then its likely a bad wire or a bad gauge? Thanks again for the help.

That is the general location of the temp sensor - and that is what the temp sensor looks like - a single wire unit that uses the engine as the ground.

You say you grounded the wire & turned on "aux" power - what is "aux" power?  An unmodified Samurai will typically have a key style ignition switch with OFF/ACC/ON/START - and the temp gauge will only work with the key in the ON position.

I turned the key to the On position, not all the way to start, so the engine was still off. The gas gauge moved but the temperature did not when it was grounded. Which makes me assume that the wiring is bad or the gauge is bad.. or I didn't have it grounded well enough haha

You're on the right track - what color is the wire to the gauge sender - if it's yellow with white stripe, it's the correct wire and if there is no gauge movement with ignition on and the wire grounded, then either the gauge is defective or it's not connected to that wire.

It is in fact yellow with a white stripe. Looks like I'll be weeding through an electrical problem... woohoo..

So last night I tested grounding the wire again, this time adding an extra length of wire to the yellow/white wire so I could reach the black connection of the battery. Sure enough when I turned the ignition to "ON" the temperature gauge rose to hot. Glad I rechecked! I'll be ordering a new temp sender now which seems like a much easier fix than finding an electrical problem. Thanks for the help!

You should be able to get the same thing grounding the wire to the intake manifold alongside the sensor - if that doesn't happen you may need to check the engine ground wires.