Does anybody know exactly how to test the ohms of a fuel level sender? I tested mine today, but I'm not sure if I did it right. Here's how I did it. Please let me know if I did it right or wrong.

The sender has two prongs on top of it. I gator clipped one with the red probe and one with the black probe. I set the meter to the ohm setting, and then I moved the level up and down. At full it read 165.4 ohms and at empty it read 20.2 ohms.

I then went on line to find a fuel level gauge and I have yet to find anything that has these settings. Did I do it wrong? The only things listed are:

Range:
73Ωs Empty / 8-12Ωs Full

Range:
O ohms Empty / 90Ωs Full

240-ohms when the level is empty
33-ohms when totally full


I set the meter to the ohm sign on the right side of the meter above the blue AC mA spot.

 

you are testing the sender properly.....now if you had a resistor of that ohm rating for full or empty you can loop it in series on the harness connector and that should make the gauge read accordingly

 

So, lets make sure I understand you right. If I go out to RadioShack and buy a 20 and or 164 resistor and put it in series with its proper post on the level it should give me the correct reading for the sender?

If so, should I leave the resistor connected to the post and run it in series with the sender wire to my new fuel guage I have?

 

I would follow the spec sheet you have and buy an inbetween number resistor so you can verify it read half or so full.....1 end of the resistor in one end of the harness and the other end into the other one I believe

 

Here's a link to the guage I have in my car. http://www.iequus.com/product_info.p...ory_id=100_105

I'm not sure i understood your last post. Do you by chance have a drawing or something showing what you mean? This electrical stuff is all new to me. I'm learning alot of cool stuff though. Thanks for all the help so far.

 

oh my bad...I thought you had a stock gauge........... well then hook the connections to the sender up to the gauge and see if they work directly..... did the gauge come with any wiring instructions???

 

I gave up on the stock gauge long ago. I even used other clusters and just decided it must be in the wiring. That's why I bought an aftermarket gauge.

Here are the instructions. http://www.iequus.com/downloads/manu...-0011.revB.pdf

The problem is, the gauge only has 3 prongs on it. Pos, Neg, and Sender. You only run one wire from the sender side of the fuel level, and the POS, NEG is just that. I even tried switching the leads all around on the gauge and it yields the same outcome.

 

your problem if the car you are working on is in fact a 1990 based on your sig is that the stock oem ford sender has a resistance of 145 ohms full and 22.5 ohms empty = oem specs and the gauge you have bought is calibrated to read full at 10 ohms and empty at 73 = opposite oem spec so you'd need a sender calibrated properly for the gauge you have bought.........on the oem sender whichever prong goes to the black wire on the harness connector gets grounded and the Y/W wire on the harness to pin on the sender is the signal wire and if your oem gauge was inopperative all you have to do to test the wiring is the y/w wire on the connector on the back of the cluster, you'd set meter to ohms and with one lead probe the y/w wire and the other lead connect it to the y/w wire down on the tank and meter should read continuity and then remove one lead and touch it to ground, meter should not read anything if it does you have a short to ground on the signal wire due to a chafe maybe in the insulation.........anyway the stock cluster has a anti slosh module that may have been bad originally if wiring is good and ground on tank is okay.......but to get your new gauge to work you need a properly calibrated sender, oem had two types a bimetalic type or magnetic type , if you are trying to use a oem magnetic type sender with a gauge calibrated for a bimetalic type you have a mismatch and not sure it'll work...either way the resistance values are mismatched for what you have right now

 

Thanks so much for all your help. I did try to find a gauge that would work with the stock level, but I just can't find one anywhere. I thought maybe if I bought a gauge that was made for Ford that would solve the problem. Unfortunately, at the time I bought the gauge, I had no ideas of how to use a multimeter and just guessed it would work. LOL, what an idiot. I think I'm just going to run the wires down from back to front and see if the wire is cut or broken somewhere. That should fix the problem. Luckly I have most of the interior already pulled out of the car because of my neutral safety switch problem. Oh well, at least I'm learning alot of useful stuff.

 

Speaking of different sending units mjr, do you know if there was a difference or which were different between the 79-85's? I'm gonna go to the junk yard and go the cheap route with in getting my gauge to work correctly. I'm tired of knowing only when I am on the last 2 gallons. I want to know where I'm at most of the time lol.