Pyrometer Wiring

[zeisshensoldt]

Tried wiring for the first time. Stripped part of the temp gauge wires and soldered onto them with correct polarity. I connected up the gauge and flipped the accessory switch, but it did not turn on/illuminate. What am I doing wrong?

 

[Jeff Nelson]

I can't tell for sure which truck wires you've connected your new wires into. Could you give me the wire numbers? If so, I'll try to help.

Edit... Just looked at the schematic. One wire (according to the drawing) goes to the temperature gauge and the voltmeter +. That will be the +24vdc wire. Leave it there and on pyrometer terminal #1. Based on your post, your other wire might be attached to the temperature sensor wire. If that is true, your pyrometer has no ground. Run the wire from the pyrometer #2 to an actual ground in the cab (dashboard screw, bare metal, etc). If the pyrometer does not come on, make sure you have 24vdc on terminal #1. Also, just a side note, you have way too much bare wire at the pyrometer and the wire is too large for its terminals. Note that not everything really needs 14ga wire.

 

[zeisshensoldt]

33 and 27. Both of them were plugged into the stock temp gauge. 27 was used as the 24v power lead and 33 as the ground.

Edit: the voltage was checked many times before and after the wires were soldered on. It reads 24v.

 

[turbovr6jetta]

Maybe check voltage with a meter... Before tapping into the wires?

 

[Jeff Nelson]

I'm not finding wire 33 on the drawing. Just run a wire from terminal #2 on the pyrometer and see if that works for you.

 

[zeisshensoldt]

Just run a wire from terminal #2 on the pyrometer and see if that works for you.

What do you mean by that? Also, Terminal #3 on the pyrometer shows a small logo of a light on and off. I don't know what that means, perhaps something to do with powering the display?

 

[Jeff Nelson]

Should have said run a wire from #2 on the pyrometer to a good ground. You should get something to light. It may be, on that particular unit, that the little light indicator is where you attach the dash light wire for external dimming for the backlight, if it has one. I'm assuming that is an LCD display, in which case it needs the backlight. Send me the name and part number and I'll be able to research it for you.

 

[turbovr6jetta]

What do you mean by that? Also, Terminal #3 on the pyrometer shows a small logo of a light on and off. I don't know what that means, perhaps something to do with powering the display?

I believe that is to dim the display when the lights are turned on. Really though, check voltage.

 

[turbovr6jetta]

Ignore the 12v labeling. They didnt make a different manual for the 24v

 

[m16ty]

It sounds like you're trying to pick up a ground through the temp sender. I think it will read 24v going from hot to the sender wire with a meter but you can't pull a load off it.

 

[zeisshensoldt]

Yep, my ground was bad. All is good now.