vauxhall vectra 2lt 1996/7 - how do i find the correct relay - millwench

the heating wire wont heat,so the car wont start, the glow plugs are ok but the heat light on dash wont come on. the mechanic has looked at a few things is now saying he needs to know the right relay for the heat wire as they arent marked like the fuses are, can any one tell me how to find the relay numbers or symblos,

thank you

vauxhall vectra 2lt 1996/7 - how do i find the correct relay - Peter D

Does it not look like this :

http://cgi.ebay.co.uk/VAUXHALL-GLOW-PLUG-CONTROL-TIMER-RELAY-9708-9503-New_W0QQitemZ320503736081QQcmdZViewItemQQimsxq20100320?IMSfp=TL100320129001r10096

Regards Peter