Speedometer head change

raceman · Jun 19, 2006

I need some info on changing out my speedometer head on my FL80. I have been told by Freightliner to set dip switches on the new one just like the old one. Did not work. Set them oppisite the old. Did not work. Tried two new units. Did not work. I have th third now. Does anyone really know how the dip switches should be set?

Raceman
OTR O/O

RichM · Jun 19, 2006

Is it legal to change the speedometer and do you have to set the odometer to the miles that are actually on the truck?

davekc · Jun 19, 2006

The dealer should be able to tell you where they are to be set. As for the milage, I think it varies from state to state. You usually have to sign something on the title as to whether it is altered or has been changed.
Or something to the effect that it doesn't reflect the actual milage.

Davekc
owner
21 years
PantherII
EO moderator

raceman · Jun 19, 2006

I know it is illegal if you just up and do it. That is why I am changing though. It is also illegal to run with one thatdoes not work. The head on mine died. That is what I am trying to fix is the milage. It must be set to the same as the old one. When you plug in the new one the computer is to set it to proper milage if the dip switch formula is set right. That is not working and the folks at FYDA are not helping with their vast knowledge. That is why I continue to run with the old one in order to retain the proper mileage but the speed is not working. The sensor and all the stuff is replaced but head is broke.

Raceman
OTR O/O

greg334 · Jun 19, 2006

As I have done this on a few vehicles lately for a couple people (outside of michigan) and done this in the past on my trucks. To remain legal is easy. You must document the changes, record the mileage of the old unit and the new unit and if there are serial numbers on the unit, record them too. Don't forget to date the document and what I did is staple the document to the title so I don't lose it. if you are unsure, have a LEO look things over and sign off on it.

Now the only time where you would have problems, or at least in Michigan is when you don't disclose the actual mileage when the title is transfered.

NEVERHOME247 · Jun 19, 2006

You should be able to set the dip switch's indentical to your old speedo head. All that does is calibrate the head so it reads correctly. The dip switch setting is dictated by a formula that includes such things as tire brand and size,gear ratios etc. There is a chart in the freightliner service manual that formulates the dip switch settings. However your old settings should be correct assuming that your speedo worked at one time. Sounds to me that your speedo is fine. But that you got a bad speed sensor. Sensor is located on rear yoke housing on the trans. Typically has one or two wire plugs. Just threads in to the hole. Only thing you need to make sure of if you change it is. If it has two plugs they go back as you unhooked them. Other then that you thread the sensor in just till it stops and them back it out a half turn. This is very important. As if you don't back it out half turn it will bust the end right off of the sensor. I would take a look at the speed sensor. Good Luck

NEVERHOME247 · Jun 19, 2006

I guess i missed some of your post. Looks like you already changed speed sensor. Like I said in my other post. Dip switch's only calibrate the head. So that it reads the correct speed. As far as it putting your old mileage on your odometer. Ain't gonna happen. You will just have to make documentation of the mileage at which you swapped the speedo head for your records. The ecm will always reflect the actual mileage on the truck. Provided the speed sensor is operational.

raceman · Jun 19, 2006

Thanks NeverHome. Yes I changed sensor. The problem is twofol. First the Freightliner folks have given me two difeerent dip switch formula and the fact the the speedometer, new one did not work either.
My odometer still works but speed needle is shot. I have to change it out and wanted to know about formula and you answered that question. I appreciate it. Now have a new unit and will call a more informed dealer to help me with the formula.

Thanks for input. I have documented the change and will assure the milage and all when I do finally get it changed.

Raceman
OTR O/O