Mark III EQ/Rev pedal help

I just picked up a Mesa Boogie EQ/REV pedal on Ebay, but I can't seem to get the EQ function to work. No matter how I set the EQ on my Mark III the EQ remains on when the pedal is plugged in. The REV seems to work fine, as it turns the Rev on or off when it's pressed. The pedal didn't come with a cable, so I'm using a standard 1/4 inch guitar cable. Any ideas, or do I need to send it back?
Thanks,

The pedal has a stereo jack socket, so you need a stereo cable that then is split at the amp end into two 1/4" mono jacks one for the reverb and the other for the EQ.
Ian

there is only one 1/4 inch jack on the back of my Mark III head labeled EQ/REV. So there's not two jacks to use for the signal if I split them with a stereo cable. :?

Anybody out there? I need some help on this one. Is there a 1/4 to 1/4 inch cable that carries a stereo signal? My Mark III head has a single 1/4 inch input for the EQ-REV signal on the back. When I plug a standard guitar 1/4 inch cable into the head, the reverb button turns the reverb on and off, but the EQ just stays on. Is this a problem with the pedal? It's a Mesa EQ/REV pedal that I got on Ebay, and If it's defective I need to send it back by Tuesday.
Help? :?

you need a shielded sterio cable. I myself have been looking for one but have only found a 10 foot mogani gold for $60 at Guitar center :evil: .

Thanks Austin! I just got a TRS cable from Guitar Center. They had a Live Wire 10 ft for $16. They have a lot more to choose from on-line. I've never needed a TRS, or balanced cable before, and that's all anyone would have had to let me know to solve my problem. My pedal now works great.