I had recently installed 3 autometer gauges in my S4 TII and have been having some troubles with them lately.

I installed a Coolant Temp, Oil Temp and Oil Pressure gauges in the center panel. When we wired them up we had all three gauges using a common 12v power source and a common ground. The oil temp and oil pressure gauges worked fine but the coolant temp gauge never moved despite the car being warmed up all the way( reading 185'F on the Palm).

The next morning the new oil pressure gauge stopped reading, the stock one still works fine.. The little light in each gauge still works but the gauges don't seem to work, the lights in the gauges are also using the common 12v and ground. I also tested the voltage at the terminals for the gauges and they are all getting 12v power. I tested the continuity of the wires to the autometer sensors and they all seem fine.

Why wouldn't the temp gauge register?

Why would the oil pressure gauge stop working?

Should I have separate power and ground for each gauge?

I appreciate any help or insight here.

 

Bad ground?

 

mech. or ele. temp gauge?

 

He tested continuity to the sensor so it would have to be electric.

 

yes electric, they have a power, ground and sensor connection on each.

The ground seems good though I could try to find a better one.

 

Did you wire them to an ignition power source so they reset when you turn the key on?

 

What I did was use the ignition wire to switch a newly installed 12v relay that has new fused power coming right from the battery.

I'm going crazy here, I just don't understand what would cause them to stop working. Like I mentioned earlier they are all getting 12v and the litle light bulb lights in each gauge.

I'm going to go outside and try to wire up a single gauge, the oil pressure gauge, and see if I can't get it to work.


Something that I did notice was that the needle moves just a hair when they power up in the two temp gauges, but nothing in the oil pressure. And when you start the car the oil pressure gauge doesn't even move anymore ( i definitely have oil pressure).


What if somehow there was a short in the wiring? Would a momentetary short be enough to fry all three gauges.? Even though the coolant gauges never worked from the get go it seems.

Sorry for
the rambling post.

 

Did you buy these used?

It's likely the oil pressure sender is bad if you're sure all the connections are good. Autometer oil pressure senders are GARBAGE. I've had several go bad. I had the exact same problem you are describing with the oil pressure. I called autometer and they said to check for continuity between the body of the sender and terminal on the end where you attach the wire. I had no continuity and replaced the sender.

I don't remember the procedure for testing the water and oil temp sending units. You need to check the sweep of resistance over a temperature range but I don't recall where to put the probes of the meter, as those sending units have one terminal instead of two like the stock thermosensor.

 

You'd attach one probe to the terminal and the other to the body of the sensor...it's just a glorified variable resistor allowing voltage to ground.

 

No I bought them new off of ebay, all three from the same seller. They looked brand new and had all of the hardware still in original packaging.

I'll try to check the continuity of the actual sender I guess since last time i just checked the wire for the sender.

The water gauge never even worked, then the oil pressure gauge didn't work one morning and I haven't had the car running long enough to let the oil get hot enough to see if the oil temp gauge still works. But what are the chances of three bad senders or gauges at the same time???

I'm going to contact the seller and see what options I have as well.

Thanks

 

when you say "body of the sensor" you mean the actual sensor itself or the threaded post off the sensor?

 

If the "threaded post" is where the wire would attach, put one probe on it.
The other probe just needs to touch the body somewhere.

If the sensor is cold (room temp) you may not see any reading at all...might have to warm it up to start seeing anything.

 

autometer is junk man, even thier boost gauge points to a box instead of zero because anywhere in that box can be 0 lol


Try tapping them into the 12v cigarette lighter source

 

I just tried separating them and powering just the oil pressure gauge with no luck. It's like the gauge just died no good reason.

I contacted the seller about a return and we'll see what he says.

As far as the boost gauge goes, I have the boost gauge fromt he carbon fiber series just like the three other gauges but it's purely mechanical so it seems to work like a champ. It seems to match up well to what the Rtek reads and the Profec B as well.

 

I have the same gauges and have no problems. Make sure you have grounded each ground wire as close to the sensor as possible.

 

This is how it was wired:



The three red wires pointing down are getting +12v from the same new relay from the battery. The lights in the gauges also get their power(white wire) from the positive post on the gauge.

The three red wires pointing up are all leading to a single 12ga ground, both the gauge itself and the gauge light(black wire)are grounded through these wires. At one point I removed the lights from the circuit to see if it mattered but it didn't change anything.

Then each gauge had a sensor wire that went to the associated sender.

I just checked and I get over 13 volts at the terminals of each gauge when the car is running.

 

There may be an issue since you wired all three gages and lights in parallel with each other. Try using three separate grounds and see if it makes a difference.

 

Well I did just try to run just the oil pressure gauge by itself with nothing else attached and it still didn't work.

 

did the directions say to use a relay?

 

the directions? no. they said to put 12v to one pin, ground the other pin and run the sensor wire to the last pin. I don't see how a relay could have anything to do with the gauges not working, especially since the gauges are getting power but they don't read, it not like they aren't getting power.

 

why aren't you powering the lights off the parking light circuit? red/green wire IIRC, which runs from the light switch to the gauge cluster to the radio area, terminating at the cigarette lighter illumination.

 

remove them all and try one at a time??

Maybe you can get ahold of autometer? might be hard to talk to tech support tho, the general idea that any tech support line applies to you when you talk to them is that you dont know anything lol

 

I didn't know about that light circuit, though I could easily swap the kights over to that power source. But the lights don't matter, even with the light removed from the gauge wiring the gauges still don't work.

I tested the oil pressure gauge by itself and it didn't work.

The water temp gauge never read anything from day one.

The oil temp gauge worked last time before I unwired everything.

 

You just have to test those senders. If the senders are bad- there is your answer. If the sensors are NOT bad, then you have wiring problems. I still don't understand the reasoning for the relay in the circuit. Relays have unlimited uses, but I cannot understand the necessity for a relay in this situation.

If the sensors pass testing, then you are going to have to rethink your wiring. No criticism intended, but it is pretty easy to screw up when wiring. Even if Autometer senders are known crap, I think it is highly unlikely that you would get 3 bad ones at the same time.

Here is a tip: Before I wire anything complex, I make a wiring diagram with wire colors noted. Then I make a procedure list and decide in advance what order to connect the wires. This clarifies my thinking and my plan. I work with one wire color at a time. I solder and heat-shrink everything possible (OK, not spades on terminals!) As I go, I cross each step off the list.

When I do this, *I never* make a wiring mistake or get lost along the way even if I have to stop in mid project to do something else that life demands.

Good luck, you will work this out. Nice dash.

 

Thanks for the info. I'm going to try to test the senders today. The thing that makes me think there is something worng with the gauges or senders is that the two oil gauges worked but the water temp gauge never worked. Then the oil pressure one stopped working. But the chances of three bad senders must be 1 in a million.

I just added the relay so that they were getting nice switched 12v, I don't really know if it was necessary but it certainly should have a negative impact on anything.

I don't know what could be bad with the wiring, it seems pretty straight forward.

Should they each have their own power and ground or it it okay to run them all from a common power and ground?