I jumped the low pressure switch. Compressor did not engage.
I followed the instructions on the manual and I checked both pressure switch (S31/1) connections for battery voltage. I got 12.4 v on one and xx mv on the other one. According to the book, if voltage is found in only one connection, I should check the high pressure of the air conditioner. What I do not know is, should it be approx. battery voltage on both or ANY voltage.? My understanding is that if I jumped the low pressure switch, the compressor should engage. Is that correct?
All the steps described in the book come back OK...except for one. The speed sensor (L4) did not give me the nominal value of 0.3 V AC. It gave me NO Volts. The resistance was .907k. The nominal value is 530 to 650 resistance. May be I messed up that test? Is that what you meant when you said "verify the compressor speed signal"?
The only way the compressor engages is by jumping terminal 5 and 7 on the 12-pole coupling...