Trim and Water Temp Gauges not working

[convergent]

I have a '95 ProCraft 200 Combo that is new to me and there are two gauges that are dead... both on the right side of the instrument panel, one above the other. When I tested the boat before buying it, I'm 99% sure the trim gauge was working, but had some problems, and I don't honestly remember looking at the water temp gauge so I can't say on that one. They are both completely dead now... needles never move at all. Before I go ripping into everything and try to trace out the wires, is there anything that might be common to two gauges in the panel? All the other gauges seem to work.

 

[Silvertip]

Re: Trim and Water Temp Gauges not working

Yes there is something common to the two gauges. +12 volts when the key is on and ground. You either have +12 volts at the "I" or "+" terminal on the gauge or you don't. Check it. Each gauge also needs a good ground. Check it. I find it interesting that you were interested in the trim gauge working when buying a boat but not the temp gauge which really a far more important gauge.

 

[convergent]

Re: Trim and Water Temp Gauges not working

Thanks Silvertip. I'll take a look at the power and ground sometime this week. I did look at them this morning but I can't find an easy way to do it yet. It looks like I have to pull the whole dash apart with all the gauges to get at it because there is way to much "stuff" up in there to go in from the floor. With it being a holiday, I didn't want to start ripping stuff apart.

Good point on the temp gauge being more important to check during the testing. I didn't have a temp gauge on my old boat, so I guess I wasn't thinking about it the way I should. I did have my mechanic do a check on everything afterward my test, but he didn't run it out on the water to have seen a temp problem. I guess I got lucky because I ran about 3 tanks of gas through the boat in the last could of days and it didn't have any major problems. It does definitely need a tune up, but ran good still. I was exercising the trim up and down quite a bit during the testing to see how it handled, so I was watching that gauge.

 

[convergent]

Re: Trim and Water Temp Gauges not working

Silvertip, I took a look at the gauges again and they seem to have blue, black, brown, and purple... at least from what I can see through the all the wiring. I am assuming the blue is for the courtesy lights because it seems to daisy chain from one to the other. I am assuming the black is ground because it is going to the bracket on the back of the gauge and also daisy chained. The purple I'm guessing is +12V, and I am guessing the brown is to the sender. I checked for continuity to the ground, with the switch turned off. I used a jumper cable ground lead to my multimeter and I'm not getting zero ohms there... getting a couple hundred ohms. Would it be advisable for me to jump the ground battery cable to one of those black leads on the frame of the gauges to see if anything changes? I don't see how that can hurt anything unless the black is not ground, but I can't imagine the wire tied to the mounting bracket not being ground. Thoughts? I'm going to check it again with power turned on to see if I'm getting +12V across the black and purple. The courtesy lights seem to work on the gauges but I'm not sure if they share the ground.

 

[convergent]

Re: Trim and Water Temp Gauges not working

I went back out and checked things with power on. I checked voltages against a bracket holding the radio in place so I only had to stick one probe up in the cluster. I get +12.xxV on the purple lead on both gauges. I get +0.16V on the black leads. On the trim gauge I had about +2.4V on the sender wire, and on the water temp gauge it was something less than +1V. So it seems to me, unless I'm missing something, that the voltage coming into these two gauges should result in a working gauge, right? So I have two bad gauges?

 

[rwidman]

Re: Trim and Water Temp Gauges not working

Silvertip, I took a look at the gauges again and they seem to have blue, black, brown, and purple... at least from what I can see through the all the wiring. I am assuming the blue is for the courtesy lights because it seems to daisy chain from one to the other. I am assuming the black is ground because it is going to the bracket on the back of the gauge and also daisy chained. The purple I'm guessing is +12V, and I am guessing the brown is to the sender. I checked for continuity to the ground, with the switch turned off. I used a jumper cable ground lead to my multimeter and I'm not getting zero ohms there... getting a couple hundred ohms. Would it be advisable for me to jump the ground battery cable to one of those black leads on the frame of the gauges to see if anything changes? I don't see how that can hurt anything unless the black is not ground, but I can't imagine the wire tied to the mounting bracket not being ground. Thoughts? I'm going to check it again with power turned on to see if I'm getting +12V across the black and purple. The courtesy lights seem to work on the gauges but I'm not sure if they share the ground.

I think you will find that the blue wire is the positive wire for the gauge lights and the black is the negative for the lights. Other than that, there is no negative connection to the gauge.

Usually, temperature, fuel, trim, etc. gauges measure the current through the sending unit. 12 volts DC is applied to one terminal on the gauge and the other terminal is connected to a wire that runs to the sender which is a variable resistor with the other end grounded. As the resistor changes to less resistance (the temperature rises or more fuel is put in the tank), more current flows through the circuit and the gauge reads higher.

See if that explanation helps you to troubleshoot the problem.

 

[rwidman]

Re: Trim and Water Temp Gauges not working

I went back out and checked things with power on. I checked voltages against a bracket holding the radio in place so I only had to stick one probe up in the cluster. I get +12.xxV on the purple lead on both gauges. I get +0.16V on the black leads. On the trim gauge I had about +2.4V on the sender wire, and on the water temp gauge it was something less than +1V. So it seems to me, unless I'm missing something, that the voltage coming into these two gauges should result in a working gauge, right? So I have two bad gauges?

Use a jumper wire to connect the terminal on the gauge that doesn't have 12 volts on it (the one connected to the sender) to ground or negative. The gauge should move to the highest position. If it does, the gauge is fine, the problems are with the wiring to the senders or the senders themselves.

If you have 12 volts on the gauge and grounding the other terminal does not move the needle, the gauge is defective.

If you didn't already have the dash torn apart, it's easier to just ground the wire at the sender and watch the gauge.

 

[convergent]

Re: Trim and Water Temp Gauges not working

Well it looks like the gauges are bad. I pulled off the sender wire and then jumped it to ground and I get zero movement on the gauge. Now I need to find some gauges that will match, or I'll end up replacing all the gauges. They are black face, black rim, and have a small blue "Q" at the bottom... and mostly white markings with a couple of blue accents. Anyone know who makes these and if replacements are available that will match?