MK1 Golf gti voltmeter, oil pressure, and temp pods

My mk1 gti has voltmeter, oil pressure and temp gauges in 52mm pods in the centre console which i believe is run of the mill gti? Problem is none of them work there is wiring going into the back of them but still not working, i think the oil pressure sender is disconnected but can't find any loose wires in the bay. I will investigate next time i work on it but wondered if anyone could give me a heads up? Previous owner converted the bottom end to 2l audi 80 does this change a great deal?

Thanks
Greg