I'm finally ready to attach the gasser economy gauge as a boost gauge and I've hit quite a snag. There are significant funcitonal differences in the left clusters although there are no structural differences. Between an early 80s 380SE left cluster and 87 SDL left cluster the relevant differences are:

- the round connector of the 380SE is missing two pins
- the 380SE doesn't have provisions for oil level, coolant level and washer level warning lights
- the park brake and service brake warning light positions are reversed

I don't know if these are as much problems as inconveniences. The potential problem is that if the pin-outs are different, it might cause problems with dash illumination unless I do some rewiring.

An alternative is to transfer the 380SE gauge unit to the SDL left cluster board. The trouble is that the SDL cluster board has a resistor where the economy gauge body goes and traces where the economy gauge input nipple breaks through the board. Not only that, it requires undoing solder joints that are difficult to reach. It might be possible to undo the solder joints by heating the back side of the board, but I don't know how to get a solder sucker thingy to the front side of the joint so the solder doesn't take a set while I'm undoing another solder joint. Aiya!

I'll look for the left cluster out of an 87 420 or 560 and see if the arrangement is more compatible with the SDL. Maybe the 380 left cluster will work with an SD.

Sixto
95 S420
87 300SDL