Post deleted because of confusing information I posted.
Comment deleted because I did not read storm9c1's post properly.I'm thinking that just putting a resistor on the G1 wire of C200 may be easier. The two circuits appear to be independent (brake test and temp gauge test). But I need to confirm that the schematics match reality on the car itself. I'll cut the G1 wire on one of my cars and see.
220 ohms is a common value. Three 1/2Watts in parallel would be 73.3ohms 1 1/2Watt. Cheap and easy to get. They take up less space. Pennies versus dollars for 1-5WattI'm also reading about 120ma draw through the 70ohm resistor into the gauge. That's approximately 1W right?
Sorry I have delusions that I can multi-task. I miss read your post and the FSM. I have deleted the part that I messed up.I think we have a misunderstanding. On page 8A-82-0, the schematic shows G1 in C200 being the bulb test ground signal to splice S212. I'm not touching a hot wire. So I'm unsure where you got S255, etc. Can you please clarify?
Oh trust me, I have the same problem often. I deleted my reply as well.Sorry I have delusions that I can multi-task. I miss read your post and the FSM. I have deleted the part that I messed up.
Good suggestion... might try that... I've seen many sealed gauges filled with that stuff. Fuel pressure gauges, for example. Still sold today as "oil filled" or "oil dampened". But I am skeptical that it's not thick enough or sticky enough for our use case. The stock fluid in these gauges are literally just a few drops on the armature at the plastic bushing/friction points. That's why I tried a few drops of epoxy resin (without the hardener). It was the stickiest goo that I could find in my shop. Nope. Then again, I didn't fully disassemble the armature either.Glycerine
This would be a separate topic.Either way, if the only way to get it onto both ends of the gauge shaft is full disassembly of the armature, that could present a challenge too. It's worth a try but not for your average DIY car guy.
Usually I use lithium (white grease). Depending on application: Lubriplate, di-electric (silicon), and Grote ultra seal are things I use.Another option that crossed my mind is the same "sticky grease" that was on 80s and 90s tape decks,
Anything above 1.5K ohms (including infinity, open circuit) will just read "C".
a 1K resistor to ground results in an approximately 1/16" deflection to the right.
55 ohms reads slightly past H.
To clarify this the temperature gauge shows a different amount of movement per degree temperature at the C end and the H end. 70degF(at C) to 200degF(middle)is 130 degrees. Middle to H is just 60 deggrees. Have a look at this generic gauge with temperatures added.Resistance temperature sensors usually have a logarithmic output.
Correct. When you turned the key on, your needle pulls hard to the left stop, far below C, which definitely means it's out of calibration.When I turn my key to run, my temp gauge moves below cold, (see video New video by Robin Schmalzbauer) so, my temp gauge does work, but the needle has spun on the shaft and now the cold (normal key on position) thinks it's somewhere below cold (the gauge is right, but the needle is wrong).
Yep. So it's working.When I ground it out, it moves to full hot (as expected).
Yep. Your understanding is correct. Either use a pot (make sure it can handle 1 watt) or even just a 55-ish ohm resistor. Since 55 ohms should read "H" on a properly calibrated gauge. My guess is that 55 ohms is going to read much below "H" in your case.f I hooked up a pot, I should be able to add some degree of resistance (or subtract? less ohms anyhow, but more than 1 ohm) and the needle would eventually move. (as it does when grounding out).
Right. This will make matters worse. Even with a properly calibrated gauge, 160 degrees is still on the cold side. Maybe about 1/4 on a normal gauge. Whereas 190 is about half way (just a guess, it's been a while since I scientifically mapped the gauge position with the sensor readings).FYI, I'm running a 160 thermostat & a tune, so I rarely see even 200 degrees.
I don't have a solution YET for making the needle stay put. I've tried several solutions over the years. Later determining that the needle spins on the shaft AND the shaft spins on the armature. So there's two points of slippage to contend with. You can try to reclock it and it may work for a while but it's almost not worth the effort until I test the resistor mod. Because the first bulb test will bang the needle hard to hot, and throw it back out of calibration. I hope to test adding a resistor to the bulb test circuit, that is your only hope (after reclocking).how would I get the needle to stay put & not simply spin on the shaft again?