volvo girl...a word of caution on the 93 940's and
coolant....(something i learned the hard way)...the coolant guage
reflects the temp of water, or air, along the route the water takes in
the engine...so, if your car has a bad coolant leak...one will notice
the heater not working (maybe...if you have it on)...then one will
notice the temp guage rise and go into the red.....then, if you keep
driving...as the coolant keeps draining out, THE GUAGE WILL RETURN TO
THE NORMAL RANGE...indicating the air temp...since the guage sensor is
no longer surrounded by hot water or coolant...just cooler air....
i hedged this problem by installing a warning light to blink, once the
coolant is near the lowest point of the plastic bottle or
resovoir...the 960's have this feature, not the 940's though....here is
some more info on this $$ saving procedure...
-------------------snip---------------------------------
Loss of Coolant Sensor Design[700/ALL] posted by Steve Ringlee on
Monday, 25 October 1999, at 12:29 a.m.
At last, I have typed the complete instructions for the loss-of-coolant
sensor for Volvo 740/940 cars. These will be posted in more readable
and better-formatted form at the FAQ within a few weeks, but here is
the first version. LONG POST FOLLOWS:
Loss of Coolant Sensor for Volvo 740/940 Cars
These plans allow you to fabricate and install a low-coolant sensor in
your car so that you can detect either slow or sudden coolant leaks and
take appropriate action before your engine overheats. Volvo 760 and 960
cars have these sensors already installed.
Overall Plan.
a) Volvo 740 with Circular Oval Tank.
Using a Nohken float level sensor switch, drill a hole in the bottom of
the coolant tank and install the sensor. One lead is wired to the front
grounding plane near the passenger-side headlight, the other back
around the engine compartment, through the firewall, to the unused
instrument panel lamp denoted "Exhaust Gas Overheating (Japan Only)."
When coolant is low, the switch closes, allowing 12V from the panel to
travel through the switch to ground, illuminating the warning lamp. You
can add a small piezo buzzer to add an audible warning, if desired. The
circuit is fused just behind the panel.
b) Volvo 940 with Rectangular Tank P/N 9142001/2
Volvo included a level float in this tank, but not the sensor. Buy a
"Level Guard" sensor Volvo p/n 3547710 and wire as above. Make sure you
read all assembly instructions first, especially to confirm you have
the float inside the tank.
Bill of Materials:
a) 740 Variant: Float Level Sensor Switch: Nohken LS-11P-0A, miniature
10VA switch with polypropylene float and stem and flat flange face.
This is available from Scientific Technologies Inc. at 6550 Dumbarton
Circle, Fremont, CA 94555-3611, 510-608-3400.
Order STI part number 22152; cost is approximately $15 plus shipping.
Web site is
http://www.sti.com
940 Variant: Volvo "Level Guard" p/n 3547710) approx $15 from Borton's
Volvo,
www.borton.com
b) Volvo 12v 1.2w lamp for instrument panel: Volvo uses two kinds of
bulbs and bulb holders for their panels. One is a replaceable bulb with
wire leads, inserted into a holder that has a plastic locking ring. The
other is a bulb soldered into a holder with metal locking tabs. You
will probably have to pull your panel to determine which one your car
has.
740 with Yazaki: Volvo p/n 2721 1.2w replaceable bulb with leads
940: Volvo p/n 966326-1 1.2w bulb fixed into holder
c) Instrument panel ell-shaped electrical connector Volvo p/n 949542
d) Electrical Supplies, all from Radio Shack (one each unless noted):
Insulated Wire: 20 gauge stranded approx 25 feet p/n 278-1225
Snap Connector 22-18 g, p/n 64-3085
Inline Fuse Holder 5x20mm p/n 270-1238C
GGS 5x20mm Fast-Acting Fuse 3/4 amp p/n 270-1048
Quick Disconnect Connector, Female, .25 inch, p/n 64-4040
Crimp Butt Connector, 22-18 gauge (quantity=2) p/n 64-3037
Shrink tubing for insulating connections p/n 278-1611
Option: Piezo buzzer p/n 273-059 (gives audible warning)
Soldering iron with electronic solder
e) Mechanical Supplies:
Wire ties for securing wire to existing harnesses
"OxGard" conductive electrical grease (from hardware store)
Silicone dielectric insulating grease (from auto parts store)
Volvo 940 applications: None other required
Volvo 740 applications: (from hardware store)
Neoprene O-Ring O.D. 1/2 inch, I.D. 3/8 inch
Neoprene Flat Washer O.D. 7/8 inch, I.D. 3/8 inch
f) Volvo wiring diagram to understand your panel connectors. Here is
where Chilton's will finally choke you, and you will be motivated to
buy the OEM wiring diagram which is absolutely the best on the market.
Approx. $30 from Ken Cook Inc. (Volvo agent) at
http://www.kencook.com/vcna/volvo.html
Assembly Instructions:
1. Volvo 940:
a) Drain coolant recovery tank and remove from car. Shake the tank to
make sure that Volvo installed the magnetic float that activates the
Level Guard inside the tank. (It rattles. If you can't hear the rattle,
install the Level Guard and test it with a multimeter for resistance
change as the tank is filled with water.) If your tank has the float,
install the "Level Guard" sensor into the snap hole on the bottom of
the tank. Insert the wire leads into the tank's wiring connector holder
on the bottom. Continue below at step "e)".
If you don't have a magnetic float inside, you can either proceed as
though you own a 740, or buy a new tank with a float from Borton's for
about $25.
Volvo 740:
a) Drain coolant recovery tank and remove from car.
b) Drill a 10mm hole on the flat surface of the underside,
approximately one inch toward the center from the threaded cap
c) Remove the float and install it so that the switch operates in the
"N.O." ("Normally open") position. Test the switch operation with the
ohmmeter range on a multimeter: when the float is at the bottom of the
switch (corresponding to loss-of-coolant) the switch should close and
complete the circuit, reducing resistance from infinite to zero.
d) Remove the fixing nut on the bottom of the coolant sensor switch.
Install the flat neoprene washer on the switch. Feed the switch wires
through the coolant fill hole, then into the hole you drilled on the
bottom of the tank. Pull the switch snug. Install the neoprene o-ring,
then the fixing nut. Snug up the nut until the switch is firmly held
without possibility of leakage. If your hole was oversize, use silicone
RTV to seal the gap between the hole and your o-ring.
e) Cut a piece of wire sufficient to reach the grounding panel just
behind the headlight. Using a short piece of shrink tubing and a .25
inch female blade quick connector, crimp the connector onto a stripped
end of the wire and add some solder to ensure a long-lasting
connection. Shrink the shrink-fit tubing onto it at the crimp to serve
as corrosion proofing. Clean off the grounding plane connector, install
the blade connector and the wire onto the ground, insulate it with some
"Oxgard" conductive grease, then feed the wire up the lamp harness back
to the coolant tank. (Maintenance note: this is a good opportunity to
clean all your grounds and coat with OxGard to prevent future
electrical problems. Don't use OxGard on any other connectors in the
car aside from grounds.)
f) Volvo 740: Install a snap connector to one wire of the float switch
and the ground wire. Again, solder it. Insulate any exposed wire on the
connector with shrink tubing. This connector allows you to disconnect
the level sensor easily.
Volvo 940: Using pliers, squeeze two female snap connectors so as to
fit very tightly on the Level Guard lead connectors. Install one of
these snap connectors onto the stripped lead of the ground wire by
firmly crimping it. Place silicone dielectric grease on the connection
for corrosion protection and connect the ground wire connector to one
of the Level Guard leads. If you are ambitious, buy the un-insulated
version of the snap connectors, solder them onto the wire, and insulate
with shrink tubing.
g) Cut a long length of wire sufficient in length to travel from the
coolant tank, up the wiring harness at the top of the firewall, thence
through the firewall rubber wiring conduit behind the driver-side strut
tower, thence into the cabin with an excess of length to reach well
beyond the panel.
h) Volvo 740: Strip, crimp, and solder one end of this wire (using a
crimp connector) to the other sensor switch wire. Insulate where
exposed with shrink tubing and apply silicone dielectric grease to the
ends of the connector to prevent corrosion.
Volvo 940: Install the other female snap connector onto the stripped
lead of the panel wire by firmly crimping it onto the stripped end.
Place silicone dielectric grease on the connection for corrosion
protection and connect the ground wire connector to the other Level
Guard lead. Again, if you are ambitious, buy the un-insulated version
of the snap connector, solder it onto the wire, and insulate with
shrink tubing.
i) Snake the other end of the wire up to the firewall harness and to
the lower firewall rubber wiring conduit just behind the driver strut
tower. Use wire ties where appropriate.
j) Cut off one of the smaller rubber wiring conduits in the lower
firewall connector just behind the strut tower. Feed the wire through
the conduit into the cabin.
k) Remove the battery negative connector to disable the electrical
system. Remove the driver side kickpanel (two plastic body mounts at
the top, pull out.) Move both the turn signal and wiper handles down,
out of the way. Remove the instrument panel (740: remove plastic fascia
plates covering the clock and tripmeter knobs, then the two screws
holding the panel in place.) (940: unclip using the two side slits
midway up the sides of the panel.) Pull the panel straight out and rest
it on the steering column.
l) Working from underneath, snake the coolant sensor wire from the back
of the firewall wiring conduit up through the panel opening. Keep it
away from the hood release mechanism, any sharp metal edges, and the
ignition module, using wire ties as needed.
m) Pull the large 12-position "C" plastic wiring connector out from the
rear top center of the panel. This connector is white and roughly "ell"
shaped when looked at from the side.
n) Confirm with your wiring diagram which connector you will use for
the warning lamp. In the 1990 740, this is position 12 on the
connector, which connects to the unused "Exhaust Gas Temperature" lamp
for Japanese applications. In the 1995 940, this is position 9 on the
connector which connects to the unused "High Engine Temperature" lamp.
o) Cut the coolant sensor wire, leaving enough to reach just beyond the
door opening. Strip and install the in-line fuse holder using soldered
crimp connectors and shrink tubing or insulating tape to cover exposed
surfaces. Install the fuse. Be very careful about soldering near the
interior of the car: use a metal guard or shield to keep hot solder off
plastic, fabric or leather components.
p) If you want to add the piezo audible buzzer, place it in-line
between the fuse and the firewall, again using crimp connectors, solder
and shrink tubing.
q) Install the special ell-shaped Volvo metal wire connector p/n 949542
to the end of the fuse wire. While this crimps in place, you should add
a small amount of solder to secure it.
r) Record the colors and positions of the wires at the "C" connector.
Snap open the back of the connector and insert the coolant connector at
the correct position. Snap it shut, making sure all the wires go back
appropriately.
s) Install the Volvo instrument panel lamp at the appropriate lamp
position, again per your wiring diagram. On the 1990 740, the lamp is
installed at the second in from the driver's side of the panel, in the
unused position. In the 1995 Volvo 940, the lamp is installed at
position 7 from the passenger side of the panel. If you are confused,
use a flashlight and shine it through the empty lamp receptacle to
confirm the position from the front. Just make sure from your wiring
diagram that you correlate the lamp position with the wiring position
in the "C" connector.
t) Re-install the "C" connector. Coil extra wire and install a tie to
keep it out of the way. Re-install the panel.
u) Seal the wire passage through the firewall conduit with silicone
caulk.
v) Test the installation.
Volvo 740: open the coolant tank and place a pencil on the float so as
to depress it to the bottom. Start the car. The lamp should go on.
Demonstrate several times to wife and kids what this lamp looks like
and what they need to do if it goes on (stop the engine ASAP and
investigate.)
Volvo 940: Using a turkey baster or a siphon, empty the coolant
reservoir. Start the car. The lamp should go on. See note above.
Regular Maintenance. Because of the peculiarities of the wiring within
the instrument panel, your bulb may not illuminate when you turn the
ignition to KPII before starting. Hence, periodically test the
installation to make sure that the bulb, the sensor, and the circuit
operate correctly by performing test v) above.
