Gauges and heaters playing up

Hello guys got a little issue after starting my car after a few weeks the heaters and gauges are playing up, firstly the heaters never came on but as I turned the knob the gauges all dropped and if i had the rear demister on it would turn off,  after a while the heaters started to work and the gauges and demister don't turn off when the heater knob is on in bit now when the car is off and the heaters are off the gauges still work and when  the heaters are on the gauges drop, never had a issue before just Happened all of a sudden the fuses all seem ok, there was no battery in the car for a few weeks a couple of wire of the negative terminal came lose so i re attached them other than that i really don't think anything has changed all help appriciated in advance  

Re-do your main Grounds battery to frame and frame to engine.

All gauges or the ones in the cluster.
For cluster only look at adding a ground to your pin 2 Brown wire straight to the frame.

Also verify that your 10V stabilizer is good, it is in the Bentley.

Wires coming loose on the Positive side or the Negative side….?


I would suspect that your having phantom ground or Positive issues, that is with things off, all is well as the path for that option is being used by something else, and when you turn it on, then what ever was using it isn't now.

Suspected components:
Ignition Switch,
Battery cables specifically Grounds.
The Load reduction relay.

 

Thanks Briano the vdo gauges that are playing up the cluster I had grounded to the frame last line incas issues, someone suggested it could be the ground claw near the fuse box, also how do I re-do my ground, sorry to sound silly, but thanks briano

If you had loose wires on the battery clamp then make sure they are properly connected and if they are in a lug then make sure that the wires are crimped tightly.
I agree with Briano that it's probably a grounding issue, you need to follow the brown wires from the heater fan, rear demist switch and VDO gauges and make sure it's clean and sound where it connects to the body and that where the wires are crimped that it's tight.
You could try running a temporary earth off the gauges to the battery to see if it cures it.
As the gauges, heater and rear demister are ignition fed it could be that you have a poor connection somewhere that means you get volt drop when the fan is running and causing other instruments etc to malfunction.
 I would check the earths first though.

Thanks saulty il check the battery negative again and see if it's ok, like you said could be the wires aint making a good contact also are the heater, VDO gauges and rear de-mister on a same connection or do they all have separate connections ?