This time the subject is the ignition switch.

As I look at the wiring diagram in the borrowed Green book (thanks again Duane, I've got my nose buried in it constantly), I see the ignition switch connection chart.

I'm basically using Volvo's convention of switch position, ie, Position 0 is key in, ignition is "OFF"; Position I is accessories only "ON"; Position II is ignition fully "ON"; Position III is "START". However, I'm adding a switch position: -I. This represents the switch with the key out.

It appears to me that there are 10 terminals on the switch labeled as such:

S

50

X (qty 2; right next to each other)

P

30

15 (qty 2; right next to each other)

30 (I assume this is internally shorted to terminal 30 above)

R

Terminal(s) 30 appear to be the pole(s) of the switch; all other terminals are the throws.

So here's what I make of it:

Position -I:

30 is connected to P

Position 0:

30 is connected to S, P

Position I:

30 is connected to X, X, R, S, P

Position II:

30 is connected to X, X, R, 15, S

Position III:

30 is connected to 15, 50, S

So the question is: What does this switch really look like internally? Per the switch schematic in the Green book (p 1) and in Bentley (pp 390-8 & 390-9), it looks like a DP4T in parallel with a SPST... then in Bentley (p 390-10), it looks like a 4P4T... Terminals R & P don't show up anywhere that I can see.

Here's another bit of weirdness: In the Green book, in the many subsections that so nicely describe the circuit, the switch is shown mechanically (a 3/4 view). The weird thing is, in almost every case, only 9 terminals are shown. Only on pp 27, 69, and 71 are all 10 terminals shown. This isn't a big deal, I admit, but inquiring minds want to know.

I realize that in order to get the final answer to all this, I'll probably need to hold a switch in my hand, and use a DMM to sort everything out. Unless someone knows the answer.

nmi

Brother. Picky, picky, picky. I suppose you're one of those detail freaks who thinks a series should be numbered sequentially.

Les -

Curiouser and curiouser. (Do you recognize the source of that phrase?) Inquiring minds want to know which Green WDM are you looking in? I have TP 30419/1 1983 models, Supplement to 1982 WMD; TP30678/1 for the 1984 240 US & Canada; TP 30808/1 240, 260 1985 and the TP 31076/1 Repairs and Maintenance, Wiring Diagrams 240, 1987-1988.

They are all the same in style and readibility. They show differences in ignition switch layouts. The Bentley indicated different year models on the 3 pages you cite.

Regards,

Bob

:>)

"Curiouser and curiouser. (Do you recognize the source of that phrase?)"

Well, I'm not sure... but the white rabbit told me if I'd just follow him, I'd find out!

"Inquiring minds want to know which Green WDM are you looking in?"

TP 30678/1 (1984 Wiring Diagrams, US & Canada).

"They show differences in ignition switch layouts. The Bentley indicated different year models on the 3 pages you cite."

Interesting thing about those Bentley switch drawings... check out Fig. 20 & 21 (pp 390-8 & 390-0)... they repositioned the order of the terminals, but they are electrically identical. And on the wiring diagrams, the switch is shown with the same terminals for all years ('83 - '93).

My bet is that none of the drawings in Bentley are exactly correct (for that matter, I don't think the drawing in the Green book, p 1, is exactly correct, either). I wonder if the ignition switch is actually two switches: A 3P4T switch (terminals 15, 50, X, P, R) and a SPST switch (terminal and S), with terminal 30 internally connected to all the poles.

I'm going to the salvage yard today to pull one (it's a lovely sunny 72 in KC today). I'm gonna get this sucker figured out one way or t'other.

"I'm going to the salvage yard today to pull one..."

Did you get one? I was gonna go tomorrow.

"Did you get one?"

No, my daily schedule blew up... ie, my 15-year-old daughter, home for Teachers' Meetings, wanted to spend time with her old man. How could a Dad say no??

So we'll put the trip to the yard on Thursday's schedule.

Checked out an ignition switch from an '87. I think they are all the same. It matches the function in my WDM circa '85.

It consists of six separate spst switches. All six have one contact in common, term. 30. Five are 'break' or form B contacts at term X, R, 15, 50 and S. Two cams operated by the key positions work against the springs to open the switches. The make or form A contact is the P term which makes when the key is inserted.

The cams are configured to allow the contacts to close when there is an "X" in the corresponding position in the function table you see in the manual.

Terms 15 and X and 30 are doubly pinned, hence 10 pins on a switch with 7.

Nice day to prowl the yard. 75 degrees.