5-8. SENDING UNITS AND WARNING SWITCHES MAINTENANCE (CONT)
g. Air Pressure Sender (cont).
INSPECTION, TESTING, AND REPAIR
Inspect wiring harness terminal (4) wire for cracked or broken insulation
or broken wire strands at connection to terminal. Repair cracked or bro-
ken insulation by applying insulation tape to area. If broken wire
strands are seen, cut wire as close to terminal as possible. Strip 1/4
inch insulation from end of wire taking care not to cut through wire then
crimp new terminal securely onto wire.
Inspect air pressure sender (5) for cracks, breaks, damaged threads, dis-
t o r t i o n , broken or missing terminal, or other damage. Replace if any of
these conditions are seen.
Inspect remaining parts for cracks, breaks, distortion, or damaged
replace as necessary.
Test air pressure sender (5) as follows:
Connect air pressure sender to a source of compressed air and pressure
r e g u l a t o r.
Connect multimeter between air pressure sender body and terminal as
Slowly increase air pressure
applied to air pressure sender
while watching pressure regulator
gage and multimeter. With zero psi
applied, multimeter should
indicate zero to 6 ohms; at 30 psi
pressure multimeter should
indicate 17 to 27 ohms; at 65 psi,
40 to 50 ohms; at 90 psi, 60 to 70
ohms; and at 120 psi, 80 to 96
Disconnect multimeter, reduce air
pressure to zero, and remove air
pressure sender from compressed
a i r s o u r c e.
Replace air pressure sender if multimeter indications in step (c)
above are not obtained.