93-97 Coolant Temperature Gauge Modification (2 Viewers)
- Thread starter RavenTai
- Start date
Content may include affiliate links. Please see terms for details.
Should I be Worried?
Ok i completed the mod. The gauge worked just fine the first time i drove the vehicle after the mod. Pretty much rose to just below center and moved from there to center over the drive I took. The next time i got in the vehicle the next day the needle went straight up to the just below center mark when i started the vehicle before it was warmed up. It is still moving around a little as expected while I drive but why is it starting in the middle before the vehicle is warmed up? Any Ideas
? Also I have 2 extra 50ohm resisters and 3 extra 110's if anyone is interested shoot me a PM with address and Ill send them your way. First come first served
.
Ok i completed the mod. The gauge worked just fine the first time i drove the vehicle after the mod. Pretty much rose to just below center and moved from there to center over the drive I took. The next time i got in the vehicle the next day the needle went straight up to the just below center mark when i started the vehicle before it was warmed up. It is still moving around a little as expected while I drive but why is it starting in the middle before the vehicle is warmed up? Any Ideas
? Also I have 2 extra 50ohm resisters and 3 extra 110's if anyone is interested shoot me a PM with address and Ill send them your way. First come first served.
Post # 429 shows my temperature gauge position dring normal driving around, this would be 80 degrees give or take a degree when the head of the engine was checked with a laser temperature reader, a steady 500 metre climb at around 60 mph will bring the needle to the middle of the gauge, coincidently exactly where it sat before the mod, this is during temps around the 18 -20 degree C mark. I have yet to see it climb past this and with the onset of summer here I am keeping an eye on it.
regards
Dave
regards
Dave
Ok i completed the mod. The gauge worked just fine the first time i drove the vehicle after the mod. Pretty much rose to just below center and moved from there to center over the drive I took. The next time i got in the vehicle the next day the needle went straight up to the just below center mark when i started the vehicle before it was warmed up. It is still moving around a little as expected while I drive but why is it starting in the middle before the vehicle is warmed up? Any Ideas
that is not right.
I figured that please help me!!!
I figured that please help me!!!
you need to pull the gauge and look at your work and review what you did.
i do not know what went wrong but something did. if your gauge is going to the "happy place" immediately then maybe you connected the wrong points or spilled some solder or you have added bad parts.
Double check your solder joints, they should be shiny and smooth not cloudy and clumpy. That's the first place I would look if you're sure it worked right initially.
Pulling it back out today. Im pretty sure the solder joints were good but they may not be. Who knows. Ill try to post some pics to get some opinions.
It's a pretty small area to work in. Make sure the solder is contained within the proper area and isn't bridging across to another line on the circuit. Kind of odd it worked, but then it didn't work. If everything looks correct, probably need to change out the diode to make sure it's not bad.
I am troubleshooting my temp gauge, and this seemed like a good place to start...
I have a '94; the mod was performed during an engine overhaul/heater core replacement, etc... The gauge seems very responsive, including dips I would swear correspond to the the thermostat opening and closing.
The problem is that the gauge occasionally dips to zero (but not quite to the bottom). Once there, it will twitch (up to 1/3, down to almost zero) a few times and then rise to a stable indication again.
At first, I thought that this is related to changes in electrical load (it only seemed to happen when I engaged lockers, what with the clicking relays and blinking dash lights), but at least once it happened with the truck idling in park.
I'm pretty sure the harness is fine; I'm pretty sure the ground is fine; I am, however, pulling the dash apart one more time (my temperature mixing servomotor only goes from 1/2 warm to full hot; still may be a bad ground, I suppose), so any advice regarding what I should check is welcome. The twitching needle is making me twitchy!
Thanks in advance!
I have a '94; the mod was performed during an engine overhaul/heater core replacement, etc... The gauge seems very responsive, including dips I would swear correspond to the the thermostat opening and closing.
The problem is that the gauge occasionally dips to zero (but not quite to the bottom). Once there, it will twitch (up to 1/3, down to almost zero) a few times and then rise to a stable indication again.
At first, I thought that this is related to changes in electrical load (it only seemed to happen when I engaged lockers, what with the clicking relays and blinking dash lights), but at least once it happened with the truck idling in park.
I'm pretty sure the harness is fine; I'm pretty sure the ground is fine; I am, however, pulling the dash apart one more time (my temperature mixing servomotor only goes from 1/2 warm to full hot; still may be a bad ground, I suppose), so any advice regarding what I should check is welcome. The twitching needle is making me twitchy!
Thanks in advance!
could be a loose solder in the gauge but i would check the sensor harness condition before i pulled my dash. coolant leaks can corrode terminals and screw them up.
do you have lots of coolant and have you done a flush recently? it could also be an air bubble preventing a temp sensor reading.
What gauge indications do bubbles cause? The harness is new, the sensor looked fine, as did the gasket (assuming I am thinking of the correct sensor; all three sensor on the USDS side of the head have been reused; the one sealed with an o-ring got a new one, the copper washer was polished and reused). Coolant is new and plentiful.
I am currently fighting a tiny leak at the bypass pipe (the pipe that goes from the thermostat housing to the head and is sealed with a couple of o-rings), so bubbles are not entirely out tof the question...
I am currently fighting a tiny leak at the bypass pipe (the pipe that goes from the thermostat housing to the head and is sealed with a couple of o-rings), so bubbles are not entirely out tof the question...
excellent guide, been reading up and down this thread.
but does the resistor need to be so much as 3watts? i am having a hard time finding resistors with these specs here in norway.
i am to do this mod on a HDJ-80, 1HD-T.
but does the resistor need to be so much as 3watts? i am having a hard time finding resistors with these specs here in norway.
i am to do this mod on a HDJ-80, 1HD-T.
- Thread starter
- #455
The 50 ohm could be less, but the 110 absolutely needs to be a high power resistor, 3 watt or higher preferred, less than 2 watts
Is a fire hazard that could burn down your truck, that resisror is disipating quite a bit of power and gets quite hot, especially as engime temperarures increase and rhe swnders resisrance drops,
Is a fire hazard that could burn down your truck, that resisror is disipating quite a bit of power and gets quite hot, especially as engime temperarures increase and rhe swnders resisrance drops,
noted.. thanks, will get the resistors as specified.
tried to search ebay, but no luck so far with these specs.
Anyone planning on doing this anytime soon?
I am going to order the resistors and was wondering if those who have not done the mod are interested in going in together as I will not just order 1 set. I live in Northern Virginia.
Also, anyone in the area who would like to tackle it together please PM me and we can set up a time to work on this.
Thanks
I am going to order the resistors and was wondering if those who have not done the mod are interested in going in together as I will not just order 1 set. I live in Northern Virginia.
Also, anyone in the area who would like to tackle it together please PM me and we can set up a time to work on this.
Thanks
Quick update, now experiencing 40+ degrees here now and after climbing a longish hill of about 3 miles the temp needle was about half a needle width above the OE central position, this is the highest I have seen. So just for data I pulled into the lay by and 'hit' the head with the laser temp reader and recorded 91 - 93 depending where you pointed the sensor. To put that into perspective since my last temps checks with the laser we have had an increase of outside temperature of 20 degrees and yet the engine has only increased it's temp by around 12 degrees the gauge reflected this temp change. One of my future mods will be getting rid of the VC fan to go electric and will have some data to use for comparison.
regards
Dave
regards
Dave
Last edited:
Dave-You sure about that? Engine driven fans have a rep for being far more reliable and moving far more air than electrics. I'd stay with the VC and the fan, but let us know what you come up with.
