I started installing some extra gauges today. I wanted to use the big hole in the dash that the air pressure gauge occupied for a tach, so I bought a smaller air pressure gauge and installed that. I also bought a voltmeter and installed that. Both seem to be working fine. I hope that Monday, I will have time to do the tach. Anyway, I was curious about something on the voltmeter which was an ebay purchase and did not come with any literature. It has three terminals on it. The ground which was appropriately marked "G", one that I decided was the live connection which was marked "I" (input?), and one marked "S" and covered with a red plastic boot. The gauge seems to work as it should with the ground and input connected. Does anyone know what the "S" terminal would be on a gauge?
Would that be the internal light connection that connects to the dash lights?
Nah, it's not for the light. There is a separate little bulb holder that pushes into a port just like my telltales.
On gauges other then Voltmeter in the SW brand. I is for ignition switched [ battery ], S is for sender, GRD is ground.
Lighting is often a plug in or twist in light that uses the case for ground and the light center wire go to the instrument switched lights.
I looked at some VDO instructions for a volt meter. They had to diagrams of the back of their meters + 12 or 24 volts, - negative ground, their light had a jump wire from it to the - terminal and the lights center wire from the light went to switch instrument light system. One of the examples have a S looking from the back side in the lower right hand side. It was just to the right side of the - terminal that had it's - mark below it. In this case the S meant nothing. There is no terminal there.
Hope something helps here.
I found a discussion online where someone was asking the same question as I did. They seemed to say that G is ground, I is ignition and S is for sending unit. The explanation was that the manufacturer uses the same case for different gauges. In this case, there is no sending unit, so the terminal is to be ignored. That may explain why it has that plastic boot on it. Anyway, the gauge works without it, so that may be true.
S is for sender. Since the volt meter does not require a sender, the red cap is placed on this terminal. The S is used with pressure and temperatured gauges (oil pressure, water temp, fule pressure, trans temp., etc). It is also used with a fuel gauge. Cheaper for the manufacturer to just make 1 housing to be used with all 2" gauges. Jack
While on the subject of gauges, I was looking at some old Eagle wiring diagrams. They use a run switch operated relay back near the batteries to connect the voltmeter lead directly to the battery (with a small fuse/CB inline.
This makes a lot of sense to me as you are measuring the battery voltage without the normal voltage drop you would find up near the dash.
FWIW with gauges, I've found that buying gauges for the fact that their needle is pointed straight up during normal operating conditions - is MUCH more important to me than the fact that they all might be the same color, look the same, etc.
Basically it's SOOO much easier to quickly glance at the dash and just see that they are all pointing up- rather than looking at each one individually (if they all point to different angles under normal conditions) to figure out if all is well. If any gauge is NOT pointing up, then it's easy to see it and focus on just that one.
I've found that "matche sets" of gauges don't usually do this, as every vehicle has different normal characteristics. So on my bus I picked a couple of SW gauges for oil and water temp, some VDO's for air pressure, battery bolts and amps, and some off brand ones for turbo pressure, EGT etc. This gives you more choices to pick a gauge that's centered at your particular normal operating parameter than do "matched sets".
MANY people who've driven the bus at night especially have commented on how easy it is to ascertain "normal" with onl a quick glance, thereby allowing more attention to the road....
Quote from: boogiethecat on September 21, 2008, 10:50:01 AM
FWIW with gauges, I've found that buying gauges for the fact that their needle is pointed straight up during normal operating conditions - is MUCH more important to me than the fact that they all might be the same color, look the same, etc.
Basically it's SOOO much easier to quickly glance at the dash and just see that they are all pointing up- rather than looking at each one individually (if they all point to different angles under normal conditions) to figure out if all is well. If any gauge is NOT pointing up, then it's easy to see it and focus on just that one.
I've found that "matche sets" of gauges don't usually do this, as every vehicle has different normal characteristics. So on my bus I picked a couple of SW gauges for oil and water temp, some VDO's for air pressure, battery bolts and amps, and some off brand ones for turbo pressure, EGT etc. This gives you more choices to pick a gauge that's centered at your particular normal operating parameter than do "matched sets".
MANY people who've driven the bus at night especially have commented on how easy it is to ascertain "normal" with onl a quick glance, thereby allowing more attention to the road....
I really like that idea....But how do I aim the fuel gauge???? ;D
Paul
Quote from: Dreamscape on September 21, 2008, 11:03:06 AM
Quote from: boogiethecat on September 21, 2008, 10:50:01 AM
FWIW with gauges, I've found that buying gauges for the fact that their needle is pointed straight up during normal operating conditions - is MUCH more important to me than the fact that they all might be the same color, look the same, etc.
Basically it's SOOO much easier to quickly glance at the dash and just see that they are all pointing up- rather than looking at each one individually (if they all point to different angles under normal conditions) to figure out if all is well. If any gauge is NOT pointing up, then it's easy to see it and focus on just that one.
I've found that "matche sets" of gauges don't usually do this, as every vehicle has different normal characteristics. So on my bus I picked a couple of SW gauges for oil and water temp, some VDO's for air pressure, battery bolts and amps, and some off brand ones for turbo pressure, EGT etc. This gives you more choices to pick a gauge that's centered at your particular normal operating parameter than do "matched sets".
MANY people who've driven the bus at night especially have commented on how easy it is to ascertain "normal" with onl a quick glance, thereby allowing more attention to the road....
I really like that idea....But how do I aim the fuel gauge???? ;D
Paul
Now if I can just find a way to make that work with these digital gauges.
Wouldn't it be possible to rotate the gauges so the needles all point up or in the same direction even if the the gauge is not straight up and down???
Just a thought
Melbo
I have VDO gages a matched set in my Eagle and they read in one direction from the top down and I don't have a problem reading them night or day good luck
Paul,
The straight up needle concept is nice and at least you have an excuse for mismatched gauges. I look at my dash would tell you that I have no sense of fashion.
The Crown Super Coach I drove way back in 1970 had all SW gauges, but they were all cock-eyed mounted in the dash. When I asked the Master Mechanic why they were all twisted around crooked he gave me a look that could have melted......! :) :) :)
All the new gauges are in and, aside from the air pressure gauge being brighter than the others when the lights are on, it all seems pretty good. The mechanic that had set my idle and no-load rpm said he did them at 600 and 2100, but if I calibrate the tach to 2100rpm, it only shows about 500rpm at idle. I'll have to get someone with a photo tach to help fine tune the calibration. I now feel I have the basic minimum of gauges to make me feel comfortable. The gauges do not point straight up, but they all are normal at a bit right of center. It's reasonably easy to spot something wrong. I am not used to perfection anyway.
Melbo has the right idea,,, at least that is how we used to do it in the race cars. As was said, you don't have time to read the gauges, only time to glance down at them. All of the gauges were oriented to have the needle straight up at 12 o'clock when everything was normal. Works very well, although i have plenty of time to read my gauges.