Hello again, this might be a simple one, I've just never installed a coolant temp sensor before, and my intake has a few different ports, so I'd like to install it correctly. The wire for the sensor had broken off at some point in its life so a previous owner took the sensor out instead of just replacing the wire from what I can tell.. Any help or info would be appreciated!
Temp Sending Unit Position?
- Thread starter dwage
- Start date
Cranky1
Banned Old Stinky Fart
The plug where the USA tag is located should work....if not, someone will chime in. So long as it sees the water below the T-stat.....
Got off work today and was planning on putting the sending unit in and wiring it up. I realized that the stock style sending unit I bought is a smaller diameter than the port in the intake, I'll attach some photos for reference. I assume either I bought the wrong stock style unit or there is some sort of adapter I need to find...
69DodgeMan
Active Member
Pipe thread to pipe thread = hardware store.
Cranky1
Banned Old Stinky Fart
In the plumbing world it's called a reducing bushing or just a bushing. I've always liked to use a brass or stainless-steel bushing there.
Turns out it's harder to find the right reducing bushing in my area I guess.. I believe the temp sender I bought is a 1/8-27 NPT thread count, and I need a bushing that would adapt to a 5/8 NPT for that coolant access on the manifold, parts have been ordered, now we wait to see if they're right or not.
In the meantime, I wanted to ensure my coolant temp circuit functioned properly, as I've put the cluster back in the truck temporarily. I had to run a new orange and black wire from the firewall to the plug, and I grounded the coolant temp sensor straight to the negative terminal of the battery. I also checked continuity from the plug all the way back to the post coming off the gauge itself, and we're good there. As soon as I turn the key, the gauge sweeps all the way until its pegged. Not wanting to burn the gauge up (recently acquired NOS, and pricey), I quickly turned it off, double checked my ground and continuity in the same locations. Everything checks out. However, when I key on with a voltmeter on each gauge post, I'm getting 12 volts, and if I've researched correctly, the volt limiter attached to the coolant gauge should bring voltage down to about 5 volts. I suppose I could remove the limiter from the gauge assembly and check it right at the battery to know for sure, I just want to make sure there isn't something I'm missing.
-update: With the voltage limiter hooked up directly to the battery, if I test at the 12-volt terminal, 12 volts are seen with no issues, if I test at the 5-volt terminal, it bounces from 0, to 6,7,12 volts at random, never settling for more than half a second.
In the meantime, I wanted to ensure my coolant temp circuit functioned properly, as I've put the cluster back in the truck temporarily. I had to run a new orange and black wire from the firewall to the plug, and I grounded the coolant temp sensor straight to the negative terminal of the battery. I also checked continuity from the plug all the way back to the post coming off the gauge itself, and we're good there. As soon as I turn the key, the gauge sweeps all the way until its pegged. Not wanting to burn the gauge up (recently acquired NOS, and pricey), I quickly turned it off, double checked my ground and continuity in the same locations. Everything checks out. However, when I key on with a voltmeter on each gauge post, I'm getting 12 volts, and if I've researched correctly, the volt limiter attached to the coolant gauge should bring voltage down to about 5 volts. I suppose I could remove the limiter from the gauge assembly and check it right at the battery to know for sure, I just want to make sure there isn't something I'm missing.
-update: With the voltage limiter hooked up directly to the battery, if I test at the 12-volt terminal, 12 volts are seen with no issues, if I test at the 5-volt terminal, it bounces from 0, to 6,7,12 volts at random, never settling for more than half a second.
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Get a solid state replacement IVR and ditch the stock one. That was probably the reason you had to replace the gauge. When the stock ones go bad, most of the time they lock on to battery voltage which fries the fuel and temp gauges.