left side parking lights and headlight dimmer/turn signal switch

[dgc2]

trying to diagnose left side parking lights blowing 5A fuse on 87 carrera. all other lights function as expected. i removed left front and rear light housings and left side headlight. nothing looks frayed or corroded. to test this circuit, i worked from 58L on the light switch and have continuity to the fuse panel (gry/blk and blk/gry on the low side of the fuse panel and gry/blk on the high side of the fuse panel). also i find no frayed wires throughout circuit. inspection of shop manual exterior lights (pg 970-65) finds the turn signal/headlight dimmer switch is also in this circuit. since i have complete functionality for headlights and right side parking and turn signal, i would ask whether failure of this switch can lead to shorting the left parking light circuit to ground. if so, can i test the turn/dimmer switch as the culprit by disconnecting this switch, along the steering wheel, and jumping selected pins between the male-female connector? which pins to test?

sorry for the long discourse, but maybe help exists on this blog. fwiw, there are many blogs that suggest lighting failures due to dimmer/turn switch. since switch costs ~$130
i would like to at least have some confidence this switch is needed?

thanks for any advice.

[ChrisHoover]

Hmm. Try breaking the circuit apart and testing. I mean anywhere there is a junction disconnect it. Meter the leg toward the lamp. Try measuring resistance to ground. B+ should be above ground. Work your way toward the fuse. At some point you’ll find the load blowing fuses.

If you think the dimmer or turn signal is the culprit disconnect them. Apply power with a jumper to the battery side of the fuse. If you have light and the fuse is not blown the switch could be your problem. If the fuse blows you need to look at the wiring between the fuse and the lamp.