Hi,  went out to work on my restoration 88 Sammy and the headlight  issue I'm having has me stumped.  I have a drivers light that is about 1/3 the brightness of the passenger.  Also on that same side the high beam does not work.  This problem is the same if I switch bulbs.  Do I have to do a rewire?  I replaced the dash harness due to mice chewing a a little of insulation from the gauge cluster wiring.  Is this a switch problem?  My grounds that exit out the the headlight harness look fine.

Thanks.

Start by checking the headlight fuses - Suzuki usually wires the headlights with separate left & right fuses and "ground switching" (the switch is between the light & ground) and this can cause some unusual side effects - such as the symptoms you describe.

Could be a fuse.  If the fuse is burnt out for a headlight, the headlight will still light up, but it will be dim.  So I'd check the fuse and if it is good, then make sure the fuse is making good connection in the fuse block (sometimes you have to take a little flat screwdriver and bend the "clips" in the fuse block so they are tighter to each other).  I recommend doing this with the battery unhooked.

It just hit me.  When I changed the harness I never checked the fuses.  Just figured they were all good.  Go figure.   I looked and the fuse in the left position was blown.  I'll go look for my old  fuse box and pull a 10A out of it and try it.  Thanks for the wake up.

Dont put a oversized fuse in there, make sure it is the proper fuse so that if there is a wiring issue the fuse blows again vrs the wiring melting.

It sure wouldnt hurt to repair/replace all the grounds between the battery and frame,engine and body, not to mention the stock grounding locations. At the age of these vehicles that will be your number one problem, corrosion on grounding locations caused by both enviromental causes as well as dissimilar metal corrosion.

Ground loops are a bitch and can do massive damage to delicate electronics such as the ECU.