...and discovered after removing the ignition and coil and moving on to the wiper switch that something was not right with the schematics. Now having read Ron’s lengthy articles on this matter I’ve got serious trepidation about how reinstalling a new harness is going to go. I plan to now tag all the loose connectors, photograph the begezus out of it and pray the loom from CVI is a match.

As it will be months before the car is back I plan to leave connected or reconnect all the gauges and switches once the dashboard is out and pull the old loom from the engine compartment and rear of the car into the passenger compartment then bag and tag it.

Does this seem sensible, doable, insane?

Any advice would be appreciated.

https://jerseyshore.craigslist.org/pts/d/brick-1969-volvo-p1800-windshield/7284286014.html
deal!!!

You can mark up the back of the instruments with a sharpie if you want. Mark the wire colours for each connection.

"...something was not right with the schematics" doesn't tell me much!...in general, the Wiring Diagrams and their color codes correspond very well to what the factory built and delivered, and any changes that were made in the long time period since, usually standout from the OE harness like a sore thumb, so should be able to be dealt with...so what's the issue?

After removing the coil and ignition, the first switch I looked at was the wiper and immediately realized that the schematics I had both the original from Service Manual section 3 and a recent colour one didn’t show the red wire which eventually led me to your lengthy articles regarding the many inconsistencies between the schematics and reality.

Not having replaced the wiring in a vehicle before I plan to pull the original out through the passenger compartment with connectors tagged then while the car is off for bodywork I will lay old and new looms out to compare and tag the new one for installation.

Does this seem to be a reasonable plan?

Sounds reasonable!

The Picture is of the Lightswitch...Item 41 here: https://www.sw-em.com/1800_Wiring_Diagram_Ch_No_10000+.jpg

Cheers

Sorry, but I’m confused which are you saying is 41?
In this photo 41 is on the left, 40 on the right.

Light Sw on left, Wiper Sw on right!

See also pix here: https://www.sw-em.com/1800_Light_Switch_Wiper_Switch_Fan_Switch_Drawing_Corrections.htm

Cheers

Ok, all good.

As for the Cigar Lighter in my ‘64, another owner has provided these photos of the same inconsistency regarding the schematics.

The Black lead of the lighter connects directly to the Un-fused Brown wire feeding the Clock that runs directly from the Battery via the Voltage Regulator and Starter, rather then as the schematics show it connected to the fused Purple wire that feeds the Map Light.

I think if you give the wire to the lighter a wipe with cleaner you'll find that it's purple too.

All of the 1800 wiring diagrams redrawn and in colour are available here for download in PDF form. Thanks Warren(?) for doing all of these.

https://www.volvo1800-120club.com/technical.htm

Derek, no I’ve given the brown wire a wipe with lacquer thinner and it’s definitely brown and certainly a larger guage then the other dashboard wiring suggesting it’s meant for higher draw somewhere in the circuit. As for the black wire on the cigar lighter it too is confirmed as I’ve disassembled the whole thing for cleaning and zinc replating the outer housing.