Thoughts on a couple of repairs

[Bill]

Afternoon
I've been looking around at some C5s and would appreciate any insight into a couple of repairs that I'd look to make on one of the options I'm keen on.

The first is an ac fault, with the following symptoms (from memory so I may have to update if I've got anything incorrect). The fan system blows hot but not cold. No HVAC codes were stored and when I pressed the AC button the light came on for a few seconds but then went out again. I suspect that the ac hasn't been used much recently and realise that there could be many possibilities (low pressure?) but does anyone know of any obvious things to try?

The second seems to be an oil pressure sensor as the analogue gauge sits at maximum and the digital gauge reads 130 psi. It looks like this is the symptom of a faulty sensor, but is there anything else to look out for to make sure that everything (apart from the sensor) is healthy?

Best regards,
Bill

 

[Pitre]

Aircon simply needs pumping up, as long as the condenser (and the rest of the system) is leak free. Changing the condenser rad is not a big job either.

 

[teamzr1]

Best when wanting to discuss techie subjects is to state what year and model your C5 is as changes are made each year
What are you using to look for DTCs tripped, a scanner or via the DIC ?
Check all HVAC fuses ?
Could be the Freon level is low
Does your HVAC head have an automatic mode ?
If so, any different if pushing the auto button ?
The control for driver and passenger, what happens if you turn both all the way counterclockwise to set to max cool ?
You need to see if the HVAC doors are being controlled or stuck
Back of engine where MAP sensor is, a small vacuum hose can come off or leaking, and that hose is the feed for HVAC doors

Did you check at the back of the engine to see if the oil pressure wiring connector is fully plugged in and no oil leak around it ?

In either problem, look below the battery and see if any signs of battery acid is flowed down right downward and has eaten hose or wiring or
even can get to the PCM that is behind that right front inner fender well
Hose for HVAC is in the wiring loom, so acid can leak into loom and cannot see the damage

Above the PCM by right A pillar is the HVAC vacuum can reserve

 

[C5Steve]

As Pitre says, AC will hopefully be a simple fix. I've had to replace the condenser and compressor on mine, condenser was easy but even a non vette garage managed fine with the compressor (although it was a pain apparently).

I recently had the same issue with my oil pressure sensor, same symptoms was pegged at max. The correct way to change it is to remove the intake, however if you search online you'll find it can be done without removing it. I changed mine without removing it, however I'm convinced there's some difference in the model years as the video on YouTube makes it look far easier than it was. If I were going to do it again, I'd either learn to pull the intake myself or take it somewhere as it was not worth the swearing and torn bleeding hands that resulted in doing it with everything in place

There are a few other jobs you can do with the intake off, it's not difficult just time consuming but there are loads of guides out there. The sensor itself I think is only £30-£40 so not a costly job either.