I just grabbed a 740 wagon and the third-center tailight wont light up, weirdly the wipers and everything else on the tailgate works. The bulbs still good, and the dash light does say that the lights out, thus theres a break in the wiring somewhere. The bulb-holder bit does not get power.

Is there a wiring diagram I can look at? Does anyone sell wiring harness's for the 740 (akin to the 240)?

PS: Its true what they say, 7-900's are a step up from more "vintage" feeling 240s.

 

many of the harnesses for a 91 should still be available from the mothership (volvo dealers).

 

I'll call them up and get a price, could be expensive though.

Through the drivers side hinge, which wire am I looking for that goes to the third light?

 

looks like your 740 wagon has two harnesses in the tailgate, part 1363290 goes through the left side hinge, and connects to various things (wiper, 3rd brake light, left side of the defroster), and it plugs into another harness part 3544787 whihc goes to (not sure, electric lock? and the other side of the defroster?)


mmm, I plugged 1363290 nito the volvo parts catalog at OEM Volvo Parts at Volvo Parts Webstore and got nada. So, maybe its N/A. In that case, I would take the harness out of the tailgate, and repair/rebuild it.

 

Thank you for looking that up, when it cools off around here I'll look into sorting out the wiring. The rear lock works too oddly enough, havent had the chance to try the defroster.

I did discover an array of spliced in wires behind the passengers taillight but I doubt they have a bearing on the issue, this car never had a trailer hitch or silly speakers so I dunno what they're for.