1999 v70 GLT Dreaded Emissions fuse blown, PTC Topic is solved

eurotrash-ed · Post by **eurotrash-ed** » 16 Aug 2020, 08:19

So here’s the long story..,1999 V70 GLT.
Air conditioner started cutting off a few times in a couple of weeks. Freon looked good, low/high switches looked good.
Let car sit or turn A/C off for awhile and it works again no problems. Recent trip from Florida to South Carolina A/C worked fine..11 hr. trip.
Next day driving around town CEL pops up..
Vida/Dice indicated emissions issues..evap,purge,TCV, 02 sensors low signal.
Fuse 5 (A/C Emissions Systems) found blown. Fuse Was also a 20 Amp instead of what should have been a 10 Amp Fuse. Previous owners must have had same issue and tried to fix it with large amp fuse..Idiots.
Seems like maybe the A/C clutch might be drawing too much current? As soon as I replace the fuse and turn on ignition the fuse pops again.. Car is in good shape and I cannot find any shorted wiring anywhere. Could something else be causing this issue in the circuit?
My VIDA doesn’t have a wiring diagram for this circuit. Can someone please share or send me a link to a wiring diagram for this circuit?
Don’t want to start throwing money at the problem needlessly. I’m going to unplug the A/C compressor clutch and see if it still blows fuses..just have to go buy some more fuses.
If it turns out to be the A/C compressor clutch would I be better off to replace the compressor, dryer and associated “O” rings along with all new fresh Freon?
Sorry for the long rant..,
Stan

Post by **scot850** » 16 Aug 2020, 09:10

Is the AC compressor noisy? Main issues are bearings failing and clutch adjustment. Clutch adjustment I have not heard causing a fuse to blow. The SC will run and then stop and blow warm air. For that you can do the zip-tie or bread clip fix to get the clutch back into adjustment and running. But as to the fuse blowing I'm not sure if they are related. I have not read anything on that that I can recall.

It is worth disconnecting the AC clutch to see if it makes a difference to isolate if it is the issue of the fuse blowing.

If you have to replace the AC compressor then replacing the drier is a must as well as 'O' rings and possibly the low pressure valve. The only other thing is the orifice tube which builds up with crap over the years. it is a pain to access.

Neil.

eurotrash-ed · Post by **eurotrash-ed** » 16 Aug 2020, 10:04

A/C compressor is quiet. Fuse 5 is labeled "A/C Emissions Systems" so I assumed it also engaged the A/C clutch through the A/C relay.
Really need a wiring diagram to know for sure.
I will probably remove the relay and see if It still blows the fuse with the A/C clutch out of the picture..I unplugged all of the emissions sensors and solenoids and A/C switches (low and high pressure) and it still blew a fuse as soon as the ignition was switched on.
If I end up replacing the compressor I will replace the orifice tube, 0 rings, dryer and oil.
Thanks,
Stan

eurotrash-ed · Post by **eurotrash-ed** » 16 Aug 2020, 10:58

Update: Fuse 5 SHOULD be a 20Amp fuse according to the fuse box lid.
Disconnected wire from compressor clutch..fuse blows.
Disconnect Main engine relay and plug wire back into compressor clutch...,fuse does not blow. Time to check other emissions sensors? PTC?
thanks,
Stan

Post by **scot850** » 16 Aug 2020, 11:49

Again I would not expect the PTC to blow the 20A fuse unless the wire is damaged and shorting. I guess disconnecting it would prove that.

Neil.

eurotrash-ed · Post by **eurotrash-ed** » 17 Aug 2020, 12:31

Neil,
Thanks..., good point. Must be a dead short to ground. I've found some wiring diagrams.
looks like the following emissions sensors are on that circuit: Fuel tank pressure sensor(doubtful cause), Purge valve,Evap valve, camshaft solenoid, both 02 sensors. wondering about the 02 sensor heater wiring being shorted to ground.
Guess I'll unplug all of them and see if the fuse still blows if not then plug in one at a time until I find the culprit.
Thanks
Stan.

eurotrash-ed · Post by **eurotrash-ed** » 25 Aug 2020, 21:20

Problem solved:
PTC is shorted out to ground. Fuse 5 (Emissions fuse) 20A was constantly blowing out as soon as ignition switch was turned to position II. PTC connector was cleaned and thought to be the culprit, but measured with ohmmeter and tested good..as soon as it is plugged in to the PTC it blows the emissions fuse 5.
PTC is probably very dirty, will replace it with a junkyard unit.
Thanks for your help and hope this helps someone else in the future.

Post by **scot850** » 25 Aug 2020, 22:16

Well done for finding this. I would never expect this to be an issue.

Neil.

Post by **abscate** » 26 Aug 2020, 02:22

Excellent troubleshooting.

I looked on the Volvo web store parts engine and can’t find either the PTC Or even the snorkel available

I bought a snorkel from FCP some tears back that had the PTC included

For trouble shooting purposes a PTC has a rest resistance of ......... Ohms

eurotrash-ed · Post by **eurotrash-ed** » 27 Aug 2020, 09:15

Looks like you can still buy the inlet snorkel with a new PTC from FCP and several others. I’ve got a spare PTC that was modified to work in the Snaab inlet snorkel for my old 850R. I think that I can use the Snaab inlet snorkel on my 99 if I install another hose barb.