dsm482

just as title says, just noticed my ac compressor not engaging..

light inside does engage, fuse under hood good, fan turns on when engaged..
freon in system .. 80 psi both sides at 50 F .. because wont engage..

i did do valves and headgasket, didnt touch anythung of ac system..

the only thing i can think there is some rusty metal i think its called thermocouple on top.. some debreee fell, when i removed it, and i blew it away with air..

any wiring diagrams.... am researching this right now, before i jump an pull things out and diagnosing. to test.

both fans work when i hit the ac button switch..

i think i isolated to the 4 wires on the top of compressor.. i can see one has litle tear in it.. anyone has diagram of this... i hate to tear my power steering pump and alternator to just find out..

i would like to check power here .... kinda tight.. so i want to make sure ... I also if i disconnect the connector to it to the thermal protector on top of comrpessor.. i can do continuity test.. is that btwenn the two wires in the connector or each to ground...

ezone

Fans run when AC is switched on, that means the system is trying to operate the compressor..

Compressor clutch is not engaging for some reason.
2 possibilities (areas) come to mind:

Bad relay (stuck) or clutch problem....

Run engine and AC.
Locate compressor clutch relay in the underhood fuse box and tap on it with a screwdriver handle a few times. If compressor starts up then replace relay.

If no....
See if comp clutch is getting powered up,
see if comp clutch coil has gone open circuit
power up clutch manually (engine OFF), push on clutch by hand to see if it will stick (gap too wide)

dsm482

ok there is two wires for thermo protector .. that should have no resistance.. two reds i believe.. and there is one wire going to the field coil, that also hooks up..

the connector that goes to the comrpessor its on the fan side mounted.. can i test thru that the thermo protector ? and which wires..

am trying to avoid to take it apart...

for the filed coil i obvisoly have to take it apart because u need to disconeect it from the thermo couple metal piece...

what the resistance for the filed coil?


I was hoping i could diagnose it, with out taking the pw pump and alternator out..

then i have it apart , they won thave my part... and i have to put the car back together to take apart again to replace it.. ouchh

dsm482

i swapped the relay, with headlight they are the same part number.. headlight light up..

problem is down at compressor... thermoprotector has one wire at the pic kinda riped..

or i might think is the field coil..

do you have a diagram of this ... and the resistance needed for the field coil...?


i can obvisoly ripped apart and find out if resistance check between thermo protector.. i was hoping to test this from the connector on the fan side that goes down to the compressor.. kinda hard to reach and see..

thermo protector is i believe two red wires to the metal thin there.. and they should not have any resistance below 120 degrees

i know clutch was good, didnt make any noise before.. i believe its one of this.. my guess thermo protector..

f--k me i just put the car back together.. would have been nice if it gave up before i fixed the valves when i had everything apart..

none of the online manual links work...

dsm482

another thing is if it has a field coil bad more riesistance than it should i believeI would be blowing fuses.... thats why i think its thermo protector.... how can i test this thru the connector of the side of the fan...... that way i verify it, drive car , till i get part, and only tear it down oncee

ezone

Hmm I didn't see your edit and pics. Hang on....

dsm482

http://www.ebay.com/itm/Genuine-OEM-...VWS8xt&vxp=mtr..

this is what i think.. any way to test this thru that plug.. part number would be nice to verify this is the one..


yeah sorry for my edits, i keep forgeting stuff)

ezone

Thermal protector has continuity.

Compressor connector has 3 wires.
Thermal protector uses the 2 outside wires. (If this were open circuit the fans would not come on)
Clutch uses center wire.
Ground wire bolted to compressor is for the clutch.


Relay ruled out?

Field coil resistance....maybe 3-4 ish ohms. What do you have on yours?


I can.


No that would not cause it to blow fuses.

ezone

I didn't find the whole AC diagram but this half has the compressor and thermal protector in the center....did not check wire colors either but this is the basic layout

dsm482

ok finnaly disconected the grey connector at the fan housing .., without taking anything out..


fitted small chineze harbor freight multimeter..( it has smaller pins)

ouside pins resistance 30
inside pin, to compressor 36

then ****ed pulled my fluke 87
outside pins resistance 15-16
inside pin to compressor housing 16.


these are little hard to hold to make a contact, with everything so tight.. but i do believe i had connection good.


shouldnt there be no resistance in outside pins.. thats what i read on some forum.. ???.. there should be no resistance.. and the field coil might be high also ..

i see a ground bolt on top of metal backet where some of these wires hook up..




As for the relay i swapped since same part number with headlight relay.. my headlights came on.. fans kick so relay has to work.... i saw two relays under fuze box that had the snowflake sign, so i swapped both... still same... there is 3-4 relays there under the hood they all have exact same part number..

ezone

Verify touching meter leads together will produce 'zero' ohms showing on the meter (continuity, no resistance).

Use paper clips as terminal probes. Flatten paper clip ends with a hammer to avoid spreading out the female terminals. Or T pins make good probes too.

Stuffing meter probe tips into the connectors can ruin electrical terminals.
I'm not sure what I'm reading here.

Measure outer wire to outer wire in the compressor plug.
Should show continuity.
It does have continuity as is evidenced by the radiator fans coming on when you turn the AC on.

You sure?

By the numbers I don't trust your meter yet.

Check using battery neg terminal as ground for the meter?


Field coil ground

dsm482

i didnt touch them together, but kinda hard to hold on compressor to get a ground.. i will recheck tommorow everything **** so ****en tight there, let me find some clips and ****...

ezone

Wait.

Key off
Remove clutch relay from fuse box.
Jumper the 2 larger terminals in the socket (paper clip).
Does the clutch click on?

This part of the circuit should be all of the problem. Relay to clutch field coil

dsm482

i dont have paper clip

ezone

Everybody needs to have paper clips. Even my mom has paper clips LOL

dsm482

ok i saw two relays with snowflake sign.. which one is for the clutch in the fusebox?

I assume i need to plug the connector back? it took me 40 min to get it apart ) you realize that..


i rather remeasure resistance at the plug tomorrow to verify.. first .. before i plug it back

ezone

Googled

#2 relay


I'd never be able to make money diagnosing anything, at that rate (it happens once in a while though)

Yes it needs to be connected if you expect it to work as planned.

Turn key on, turn AC on, make sure fans still turn on when you turn the AC on...just to verify it's connected and you didn't hurt the terminals.

Then turn key off, jump relay socket (the larger pair of slots) see if clutch clicks on.

I ohm test the clutch field coil from the relay socket too.

dsm482

look at you short cuts, then why am I digging to get this small connector apart?)

i just zeroed out my leads on my fluke 87 for resistance..

what should i ohm test from the relay? u killling me , way past my nappy time

ezone

Short cut was me trying to tell you the thermal protector is ok because the fans kick on.

dsm482

I still have a broken wire to isolate on it on the compressor , well stripped from old age cracked whatever look at picture

ezone

I did look at the pics, I couldn't tell what exactly I was supposed to see though. Which wire is the problem?

dsm482

ok i took the relay out its one big relay, i did what you said, jumpered the big terminals, key off, didnt hear no click.. i have the wheels on ... is there resistance test i can do thru here?

i did verify the fans work before hand

ezone

It's not a big relay it's a small relay look at the numbers in the fusebox diagram

NOT the colored part

ezone

Assuming you locate the correct relay.....and remove it

Diagram of relay
Jumper slots in the fusebox for pins #3 and 5 clutch should click on (I assume it will not click?)

One of those slots (3 OR 5) should have 12v+ all the time

the other (5 OR 3) goes to the clutch field coil. Ohm test between this slot and a good ground (batt neg post)
Coil should be around 3-4 ish ohms

dsm482

**** .. ok i didnt short anything else out.. i just started the car...

i dont have numbers in it.. there is two relays signs only.. that diagram is wrong..
one snowflake an contacts, the other snowflake and radiator fan...

better make sure before i send power somewhere i dont need to .. i just did that with the big one.. u had the diagram above.. i didnt cause damage

ezone

Compressor clutch relay is still #2 in the diagram I posted

dsm482

ohm test , confused here.. one 5 or 3 to battery negative post ... i should have 3-4 ohm?

dsm482

I am an idiot yellow color i saw haahhahaha i taught you colored that for me

ezone

Meter neg (black) lead to battery neg post
Meter pos (red) lead.... in your hand

First set voltmeter on volts, see which terminal has 12v+ in it. (#3 OR 5 in the relay picture)

The other terminal goes to clutch. Set meter on ohms to test that terminal.

ezone

Hell no I can't work on a laptop that fast.
That was straight out of google images.

I typed out "#2" for a reason.