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Show uu HOW TO TEST MOTOR LSiPS 3 i M I One of the most annoying occuron-,ccs occuron-,ccs while driving at night Is to have 3 . ono or more of the lights go out. The t causes aro many and varied, but a f ! little knowledge of tho lighting sys-, sys-, j tern and a little experimenting will ; , soon enable the average motorist to !j locate all ordinary troubles. Ho must 2 first familiarize himself with the few 1 wires necessary to 'carry the current from the battery to tho lamps, leav- t ing the rest of the system for later 2 study. If the instruction book that 5 comes with the car is available it will I be of great assistance. I Begin by locating tho following: J First, tho battery, which may bo on 5 tho running board, under a seat or S slung on the frame, usually under the I floor boards; second, the ammeter, 8 j which is carried on the dash or instru-j instru-j ment board; third, tho switch, on I steering column or on tho instrument ! board near the ammeter; fourth, the fuse box, which is usually near the switch or under the hood, and, fifth, the various lights. INext trace tho path of the current from the batterv to tho l.nmn. 3 back again, using the diagram in the instruction book, if possible. Start at tho battery aud trace it to the am-j am-j meter The ammeter indicates whether the battery Is charging or discharging, and so is the first piece of apparatus' to be reached. The current now passes I to tho switch, with which the fuse block is usually closely associated. The fuses are short lengths of wire incased In glass. Tho wire is made of lead and tin and mlts at a low temperature. If a short circuit occurs on any lino leading to a lamp tho heavy rush of current is too great for the fuse, which melts and breaks tho Circuit, stopping the current and tho danger as well. If the hcaw rush of current were allowed to continue, tho battery would be discharged and ruined, or the wires would become red-hot with the possibility of setting fire to some part of the car. Having located the switch and fuses, it should bo an easy matter to trace tho current to tho lamps. Some systems ground tho current at the lamps, and it returns by way of the frame of the car. This Is known as tho "slngle-wiro" system. Other sys. terns provide a return wire from lamp to switch, and arc known as "two-wire" "two-wire" systems. This Is easily deter-mined deter-mined by noting whether the wire trom switch to lamps is single or double lit is an important detail when it comes to tracing the current. By tracing both wires from the battery one will be found grounded to the frame. In case all tho lights go out, look for somo trouble at tho battory. such as.a loose wire or terminal, or a short circuit on somo part of the wires leading lead-ing from tho battery. Follow along the line by the ammeter, looking for loose or brokon wires or short circuits, to the switch. Any trouble which affects tho whole system must be on a part of a circuit common to all tho lights. We do not suspect a worn-out battery, as this trouble usually comes on gradually grad-ually and gives ample warning by the lights being dim, brightening as the engine speeds up. |
