temp gauge questions

[rickrmf]

Does anybody know what the voltage should be at the sending unit, on a 4.0 ohv engine? I put a gauge cluster from a 98 explorer in my B4000 mazda, and everything works like it should, except the temp gauge does not go up very far. When cold in the morning the needle is actually below the "C" mark, and never goes up more than a third of the way on the gauge. I'm thinking that the sender I switched out could be off, and I'm going to try that, but thought i'd ask here if anyone had seen this before. I used a sender from a 98 explorer.
Thanks in advance, Rick

 

[kimcrwbr1]

ground the wire from the sensor at the temp sensor the guage should show hot you can try a different sensor but if the other guages are working good that or a wire or connector or the guage itself is all it could be. Do you have a stock thermostat and I am not sure what you voltage should be at the sensor but for earlier models you get a pulsating voltage that feeds all the guages the sensors provide the ground for the guage. You can go to the bone yard and get different years sensors and mark them to see which one works the best for you. If you haven`t changed the t-stat It might be a good time to get a good one first before it gets hot out and see what that does. Is there a paticular reason you are concerned I suggest flushing the coolant system and putting a t-stat in before you mess with the guage then you know where you stand.

 

[rickrmf]

temp gauge reply

My concern, if you can call it that, is the new gauge set up does not read the same as the old one. Also the part about the temp gauge starting out way below the "C" just looks funky. I noticed just the other day, when I put the key in, and turn it to just the on position, the oil pressure gauge makes a little jump, so that it is just to the bottom of the range. The temp gauge does not do this. I've done the grounding test before and the temp gauge will go full hot. I've been wondering if maybe this condition is the norm, and the old gauge might not have been correct! I do see that the temp gauge does not have a stop peg like the other gauges, but I just think it's kind of weird that this one starts out so far below the actual sweep of the gauge. When started cold, the needle is probably 3/8" away from the start of the gauge. I put a new t-stat in when I did all this. The truck runs fine, and I'm sure it's coming to temperature, and not running hot. Just as a note the truck is a 96 Mazda B4000, with a 4.0 V-6, and the gauge cluster came out of a 98 Explorer with the same engine.
Thanks for the help so far, Rick