Hi all,
I just bought this 93 Bonneville SSEi. Pretty sweet car. The HUD will only show the speed in KM/H. I hit the switch on the dash, nothing happens. All the other displays of the HUD work correctly. Being how I just bought it, I don't know any of its prior history (how long this has been happening...etc) Thanks for helping out guys.

You mean the switch down by the aiming ****, right? You may need to pop the dash trim off and fiddle with the switch, a connection may have come loose.

The dash trim does literally pop off. Use a long screw driver and pry where it feels connected. It'll come right off.

I'd bet the Connector to the back of the switch is loose. Check the switch for continuity from Cell 9 (Black/White) to Cell 10 (Light Blue), In one of the switch positions you should get continuity.

Alright, thanks. Will give it a shot in the morning and see how it goes. I think I'm going to have to take the instrument cluster out anyway to clean those connectors anyway. (I've got the flickering DIC-compass issue I believe. It'* intermittent, but that will prolly fix it).

I got the panel off, nothing was loose behind the HUD switch. I reseated them anyway but still nothing changed. Then this is funny, today coming home from work after I turned my car on it was in MPH. Sounds like there might be a bad ground or something?

Umm.... The switch grounds into the same place the HUD does... Do your have problems changing the brightness of your HUD?

I'm thinking that if the Km/H selection is the only thing that'* not working, it might be just a glopped-up switch. It'* a push-in/push-out switch, and if it'* hardly ever used, its mechanism can get a little gunked up.

If I remember right, it should make an audible click each time you press it, and as I said above, it should be a pop-in, pop-out movement; i.e. selecting Metric should leave the button in; pressing again for MpH should pop it out, or maybe vice-versa. I'll check mine tonight to be sure. I already looked at the PDF version of the owner'* manual here, but they don't get into that much detail about it.

when the switch is out, it'* MPH, and you should measure continuity across the bottom two pins.

I pulled the switch this afternoon and cleaned the connectors. Also the switch does make a click when I push the mph/kmh button. I can't find my multimeter at the moment so I'll test tomorrow. I also pulled the instrument cluster and cleaned all the oxidation. I know it'* not connected to the HUD but I also have the blinking DIC/Compass issue.

BTW, when I test for continuity....omg i'm a newb, do i have the ignition on or off?

Thanks guys.

You have the switch in your hand

I meant there should be continuity across those pin of the switch, prolly should have mentioned that...