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Topic: Why does my speedometer and tach not light up with headlights  (Read 531 times) previous topic - next topic

Why does my speedometer and tach not light up with headlights

Why does my speedometer and tach not light up with headlights on?

1st photo shows dash with headlights on.  And everything lit up but the speedometer and tach.

2nd photo shows dash with headlights off, speedometer and tach lit up.


2000 GV320 4010 build #5712  2019-?
1999 Bounder 2000-2008
Bardstown, KY
🥃The Bourbon Capital of the World🥃

Re: Why does my speedometer and tach not light up with headlights

Reply #1 –
A wiring problem.

Sounds like an accidental burglar alarm circuit.

Follow the Speedo/tach lamp feeds. They should be on the same cut as the rest of the instrument lamps.

Tim
Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: Why does my speedometer and tach not light up with headlights

Reply #2 –
Since the tach and speedo lights work with ignition on (full bright), and with the running lights on (dim-able), there should be a relay involved. The bulbs would feed from the relay common, ignition would feed normally closed, and the instrument light dimmer would feed normally open. maybe a bad relay or open connection on the N.O. side.

Ours should be the same. I'll look at my dash schematic tomorrow and confirm/refute this assumption.

Greg
Greg & Cathy
2000 U320 4010 DGFE Build #5650
Had: 1999 Tradewinds 7370

Re: Why does my speedometer and tach not light up with headlights

Reply #3 –
Thanks for the input!

2000 GV320 4010 build #5712  2019-?
1999 Bounder 2000-2008
Bardstown, KY
🥃The Bourbon Capital of the World🥃

Re: Why does my speedometer and tach not light up with headlights

Reply #4 –
Tommy,

I totally forgot to look at my drawings. Fortunately, the grain O wheat lamp between my ears was dimly lit this PM and I remembered.

Attached drawing confirms there is a relay involved. It appears N.O. and N.C. are reversed from what I mentioned.

Greg
Greg & Cathy
2000 U320 4010 DGFE Build #5650
Had: 1999 Tradewinds 7370

Re: Why does my speedometer and tach not light up with headlights

Reply #5 –
Quote from: MisterEd –
Tommy,

I totally forgot to look at my drawings. Fortunately, the grain O wheat lamp between my ears was dimly lit this PM and I remembered.

Attached drawing confirms there is a relay involved. It appears N.O. and N.C. are reversed from what I mentioned.

Greg

Thank you sir!


2000 GV320 4010 build #5712  2019-?
1999 Bounder 2000-2008
Bardstown, KY
🥃The Bourbon Capital of the World🥃