Temp guage reading wrong

[Johnny89345]

The trucks a 2000 k3500 6.5. I replaced the coolant temp switch in the head. I also jumped the single green wire to ground and the guage shoots to full hott. The guage at operating temp only goes a quarter of the way. Anyone have an experience with this. And i added additional grounds from
batt-block
Block-firewall
Boock-frame

 

[stutaeng]

I don't have experience with the 6.5TD, but my 5.7 00 K3500 has this problem as well. I think that temperature sender goes directly to the cluster, so I'm guessing the cluster is to blame. I changed the sender without any change. When I've hooked up my scanner, it does read 190F. So I just run it like that.

I think there's another member here that has the same exact issue...maybe @frito-bandito ? That, and our speedometers read too fast!

 

[someotherguy]

The gauges aren't known for being accurate. Once you've exhausted the options of replacing the sending unit and making sure your grounds are good, you could consider a hack:

If you have an IR thermometer, scan for max temp right at, and around, the thermostat housing with the engine fully warmed up. You should get a reading very close to your thermostat rating. Then pull the cluster, remove the lens, and carefully pop the needle off the temp gauge. Re-install the cluster and fire the truck back up, so that the gauge's stepper motor is positioned where it *thinks* it should be.. and then place the gauge needle at the reading it *should* be at.

Does this fix the problem? Nope, but it will now read correctly when it is at the expected operating temperature. If it goes over that reading you can be pretty well assured it is running hotter than it should.

Richard

 

[stutaeng]

Well, that's easy enough!

Same for the speedo Richard? I may have a hard time driving 70 MPH while trying to do that method, LOL! Thankfully my cruise control still works.

Now that I think about it, I once took apart my 99 Silverado NBS because of that crappy solder causing the odometer to go out. I didn't "clock" the temperature and fuel guage needles and had to do this when I started it up after re-soldering it. Had to fill up the gas tank for the fuel needle.

BTW, I think they recommend a fork (as an eating utensil) for removing the guage needles IIRC.

 

[east302]

The guage at operating temp only goes a quarter of the way.

Sounds like my three 98s. They read halfway between 100 and 210.

In other words...it’s probably how it’s supposed to be. Ford had a novel solution - they just wrote the word “Normal” across the dial range and called it a day. It probably cut down on the number of customers wanting inaccurate gauges fixed under warranty.


Sent from my iPhone using Tapatalk

 

[frito-bandito]

I don't have experience with the 6.5TD, but my 5.7 00 K3500 has this problem as well. I think that temperature sender goes directly to the cluster, so I'm guessing the cluster is to blame. I changed the sender without any change. When I've hooked up my scanner, it does read 190F. So I just run it like that.

I think there's another member here that has the same exact issue...maybe @frito-bandito ? That, and our speedometers read too fast!

My temp gauge has been seemingly accurate, but yes, my speedometer was 10mph too fast even with stock tires. I’ve since upgraded to 265’s and it didn’t fix my speedometer inaccuracies.

Funny story though....when I installed the Escalade cluster, my speedometer is now dead on. Only thing I changed in the Esky cluster was the fuel gauge stepper motor and the odometer...but I need to go back in there and replace the trip meter too apparently.


The fuel gauge in the Escalade cluster vibrated badly and slapped the temp gauge when I was starting the truck. I simply took a pic of the fuel needle position on my old cluster, used the fork method to remove the needles, and swapped steppers, then put the needle back on after I installed the cluster and had the truck running.

 

[stutaeng]

My temp gauge has been seemingly accurate, but yes, my speedometer was 10mph too fast even with stock tires. I’ve since upgraded to 265’s and it didn’t fix my speedometer inaccuracies.

Funny story though....when I installed the Escalade cluster, my speedometer is now dead on. Only thing I changed in the Esky cluster was the fuel gauge stepper motor and the odometer...but I need to go back in there and replace the trip meter too apparently.


The fuel gauge in the Escalade cluster vibrated badly and slapped the temp gauge when I was starting the truck. I simply took a pic of the fuel needle position on my old cluster, used the fork method to remove the needles, and swapped steppers, then put the needle back on after I installed the cluster and had the truck running.

Ok, good to know. Maybe it's @1ton-o-fun then that has that temp. guage that reads low like OP? I hope I didn't dream it! I confuse you guys, LOL.

 

[Johnny89345]

Maybe i should have added its a cucv 12/24 volt system in series. Ive been sorting through wiring issues since the day i got this truck.

 

[kenh]

My 90 C1500 with a 5.7 temp gauge would work when it wanted to. Sometimes would work just fine for two or three days then go dead for a week or more. Checked and cleaned grounds, removed and cleaned threads on sending unit. Ground sending unit wire and gauge would read temp but not full scale.

I replaced the gauge and that solved the issue.

Ken

 

[deckeda]

I would have started a new thread with this same title, but I haven't done the same work. Temp gauge is pegged now all the time, is the first step to look at wiring or to test the sending unit? I see one on the driver's side in that head but don't know if that's the only one this orig 7.4L TBI has?

1989 C3500