A r elay cann ot be repair ed or adjusted and, if
faulty or da maged, it mu st be replaced.
OPERATION
The ISO relay consists of an electromagnetic coil, a
resistor and three (t wo fixed an d one m ovable) elec-
trical con tact s. The movable (common feed) relay con-
tact is h eld a gainst one of t he fixed conta cts
(normally closed) by spring pressur e. When t he elec-
tromagnetic coil is en ergized, it draws the movable
contact away from the n orma lly closed fixed contact,
and holds it a gainst the ot her (n ormally open ) fixed
contact.
When the electromagnetic coil is de-ener gized,
spring pr essu re returns the m ovable conta ct to the
normally closed posit ion. The resistor is connect ed in
pa rallel with the elect romagnetic coil in the relay,
and helps t o dissipate volta ge spikes th at are pro-
du ced when the coil is de-en ergized.
DIAGNOSIS AND TESTING - RELAY
(1) Remove the rela y from its mou nting location.
(2) A relay in the de-en ergized position should
have continuity between term inals 87A an d 30, an d
no continuity between term ina ls 87 and 30. If OK, go
to Step 3. If not OK, repla ce the fa ult y relay.
(3) Resista nce between termina ls 85 and 86 (elec-
tromagnet) shou ld be 60.7 - 80.3 ohm s. If OK, go to
St ep 4. If not OK, replace the fau lty relay.
(4) Connect a bat tery to t erminals 85 and 86.
There should now be cont inu ity between terminals
30 and 87, and no cont inuity between t erminals 87A
and 30. If OK, perfor m the Relay Cir cuit Test th at
follows. If not OK, replace t he fau lty relay.
DIAGNOSIS AND TESTING - RELAY CIRCUIT TEST
(1) The relay common feed ter minal cavity (30) of
the fuse block is connect ed to ba tter y voltage and
sh ould be hot at a ll tim es. Check for battery voltage
at the fused B(+) circuit cavit y in the fu se block
recepta cle for th e relay. If OK, go to Step 2. If not
OK, r epa ir th e fused B(+) circuit to the fuse block
fuse as r equired.
(2) The relay norma lly closed term ina l (87A) is
connect ed to terminal 30 in t he de-en ergized position ,
but is n ot used for this application. Go to Step 3.
(3) The relay normally open ter minal (87) is con-
nected t o th e common feed term inal (30) in the ener-
gized position . Th is ter min al supplies battery voltage
to the fused B(+) fuse in t he fuse block tha t feeds the
accessory when the relay is energized by th e ignition
switch . Ther e should be contin uit y bet ween the fuse
block cavity for relay terminal 87 and the fused B(+)
fuse in t he fuse block at all times. If OK, go t o Step
4. If not OK, repa ir th e open fused B(+) circu it to th e
fuse block fuse as required.
(4) The coil gr ound terminal (85) is connect ed to
the electrom agnet in the relay. It receives ba ttery
feed to en ergize the rela y wh en th e ignition switch is
in the Accessor y or Run position s. Turn the ign ition
switch to the On position. Check for battery voltage
at the fused ignition swit ch output (acc/ru n) circuit
cavity for rela y termina l 85 in th e fu se block recep-
tacle for th e relay. If OK, go to St ep 5. If not OK,
repair the open fused ign ition switch ou tput (acc/run)
circuit to the ignition switch as r equir ed.
(5) The coil battery terminal (86) is connected to
the electr omagnet in t he relay. Th e fuse block ca vity
for t his termina l should ha ve continuity t o gr ound at
all times. If not OK, repa ir the open grou nd circuit t o
ground as requir ed.
REMOVAL
(1) Disconn ect and isolate the negat ive ba tter y
cable.
(2) Remove t he rela y by gra sping it fir mly a nd
pu lling it st raight out from it s receptacle. A sligh t
back an d fourth rockin g motion may help th e
removal process.
INSTALLATION
(1) Position the rela y to the pr oper r eceptacle.
(2) Align th e relay termina ls with the term inal
cavities in the receptacle.
(3) Push fir mly and evenly on the top of t he relay
until the terminals ar e fu lly sea ted in th e t erminal
cavities in the receptacle.
(4) Connect the n egat ive batt ery cable.
VA 8W-97 POWER DISTRIBUTION 8W - 97 - 5
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