I am looking at the pages 360-11 thru 360-15 of the BIG Bently book and have question about the item noted as

"Mercury retard switch" in Figure 33 page 360-14


1) What is this switch for?

2) Where is it located?


The unit on my 83 is a DanaCorp Unit
Cruise Control Speed Assy

Volvo P\N 127 27 96
Dana Corp Perfect Circle Div
P\N 53C--13101 -- R

Thanks for any help Bob

Yeah it is a safety thing. I think it meant to disengage the cruise in a crash or rollover too. Its on the passenger side firewall. It looks like a black bar (bout 3/4 inch wide, inch long) sticking out from the firewall at an upward angle. Is seems to me Hanynes goes on about the correct angle, but it is bent so that it is on the right angle when it is screwed onto the firewall.

the word "mercury" means "vacuum" when you set a speed, the cruis control uses "mercury"/vacuum to hold a diafram that holds the throtel open, when the car goes past a certain limit usualy one or two mph over the set speed, a triger tells the mercury retard switch, to retard the mercury (lower the vacuum)and the diafram moves and the throtel plate closes, than the car slows down. when the car accelerates, thats the mercury retard switch giveing more mercury (more vacuum) to pull that diafram and open the throtel plate. I dont have that manual but this is close hope it helps
--
Kevin * HONDA spanking,1985 240DL * VOLVO ON!!!!

Hi rjs -

The mercury retard switch is, I think, a device to cut out the cruise control when the car either decelerates or goes down hill. When the downhill or decelerate conditions ends, the cruise control will kick back in automatically. It's kinda neat - I can feel it doing its thing on my car.

It is mounted, again I think, on the firewall near where the other stuff is, above the 02 sensor.

Are you installing Cruise on your brick?

Good Luck,

Bob

:>)

The "mercury switch" ---- yeah, I saw the little booger mounted on the Cruise Control unit on the firewall and wondered what it was. It's all covered up in a heat shrink skin and pointing up at about 30 degrees. I'm agreeing with the safety reason. I use mercury switches all the time for switching heavy current loads and other reasons, but couldn't find or figure what this was.

thanks for the help

bob