1979 Ski-Doo Supplementary Shop Manual, Page 143Get this manual
SECTION 05 SUB -SECTION 03 (ELECT RICAL TESTS)
Battery replacement
1Remove the four (4) screws securing cover to case2 Carefully lift cover3Replace batteries with size "C" Alkaline batteriesBe sure to observe polarity markings on battery holder or lamp will not light
4Carefully install cover on case being certain that no wires are pinched between cover and caseSecure cover
NOTE: Weak batteries will not impair tester operation or calibrat ionThe light wi ll glow dim
The ign ition tester may give false readings if the rivets on the back cover come in contact with metal