1800 Light Switch, Wiper Switch, Fan Switch Drawing Corrections              
Jun 2014 R. Kwas, changes on-going (mostly when the spirit moves me)


Light Switch
Wiper Switch
Fan Switch


Background:   On the Volvo factory wiring diagrams of early (carbureted) 1800, the internal switching shown for Lights, Wipers and Fan switches is just plain wrong, showing in each case oversimplified connections which donít allow for the sequential nature of each of these multi-position pull switches. 

Now this is not a huge problem that would bother anyone but the writer, but it is the writerís opinion that what is shown should be correct, making it infinitely more useful if one was engaged in troubleshooting problems involving those circuits. 

FIGURE 1.  1800 Factory Wiring Diagram Extract with incorrectly shown internal connections of:
1.  Light Switch, 2. Wiper Switch, 3. Fan Switch, highlighted.

  Picture of (Lucas' finest, insert choking sounds here!) switches in question.  L to R, Fan, Wiper, Light. 
The Rheostat for Variable Instrument Lighting is located in the white ceramic visible here. 
(Fuzzy) Picture credit:  Stolen from some E-Pay offer, Condition:  Gently used and abused, but sold As Is!


1.  Light Switch:  The typical published Wiring Diagram shows an oversimplified switch, with Power input terminal connected to a contact arm which connects to EITHER Marker Lights (to the right) OR Headlights (switched to the left), suggesting this is a Single Pole, 3 Throw (SP3T) switch.  That is clearly incorrect.  The correct representation is sequential as shown here, applying power to Marker Lights in position 1, and Markers AND Headlight (Mainbeams) in Position 2.  

FIGURE 2.  The 1800 Light Switch showing oversimplified representation of Wiring Diagrams on left,
and corrected, detail with sequential connections of Marker Lights and Head Lights on right. 



FIGURE 3.  Picture of an 1800 Light Switch, once again graciously made available for my disassembly, and up close and personal inspection, by Chris Horn (a.k.a. Agent Strangelove). 


2.  Wiper Switch: 
The typical published Wiring Diagram similarly shows an oversimplified switch.  Detailed, correct connections are shown here, and covered in detail under the Wipers Tech Article LINK:  Windshield%20Wiper%20Systems.htm#Different_Motors_and_Different_Circuits


3.  Fan Switch: 

Finally, the Fan Switch, again is shown oversimplified and incorrectly.  The correct representation is really as shown in the 122 factory Wiring Diagram, showing sequential connections which allow for two speed operation.   

FIGURE 3.  Fan Switch wiring detail.  Oversimplified and incorrect extract from 1800 Wiring Diagram on left (probably drawn by some Lucas employee doing his part of killing the British car industry), and the correct extract from the 122 wiring diagram on the right, drawn by a Swede who was paying full attention! 



This information is Copyright © 2014-2016 Ronald Kwas.  The term Volvo is used for reference only.  I have no affiliation with this company, other than to try to keep its fine vintage products working for me, and to help other enthusiasts to do the same.  The results and information presented here are my own experience, and can be used or ridiculed and laughed at as you see fit.  As always, if you can supply additional objective info or practical experience, Iíd appreciate hearing it, and will consider working it in to the next rewrite of this article...along quite possibly with the odd wise-a** comment, if I can possibly work that in. 

You are welcome to use the information here in good health, and for your own noncommercial purposes, but if you reprint or otherwise republish this article, you must give credit to the author or link back to the SwEm site as the source.  If you donít, youíre just a lazy, scum sucking plagiarist...so the Boston Globe wants you! 

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