T660 speedometer problems

[Rawze]

(11-16-2018 )senorbac Wrote:  

(11-16-2018 )Rawze Wrote:  Could it be a bad connection on the circuit board in the back of the unit? - Does it start working when the insides of the cab warms up good?

just some guessing here.

Could it be the connector on the speed sensor? Since no it doesn't get any better if the inside cab gets toasty.

could be. Maybe check what the engine is reporting to verify it is not the gauge. Paccar products seem to have speedo gauge issues a lot, so just saying to don't rule it out.

Also check the plugs that go into the cab where they meet the firewall.