Can you buy an instrument control box seperate from teh instrument cluster or is it the same?
Depends On What You’re Trying To Control. Why Not Give Us The Model-Year And The Exact Nature Of The Problem / Concern ?
CSA
Im sorry. My speedometer and rpm and temp gauges have been going crazy. Car drives fine. My husband said I need to call and order an instrument control box. I told him the guys on car talk said its most likly the instrument cluster, so my husband said we only need the instrument control box. But I can not find this anywhere online so I thought my husband is wrong as far as what it is called. I think its one in the same? Thank you for your help 
opps 2000 Nissan Maxima SE
Sounds like a bit of a shotgun approach to me.
There are sensors that control those gauges; any of them could have gone bad.
Removing and replacing the instrument panel is a pretty major job in modern vehicles. That would be my last resort, personally. Good luck.
Nissan calls the instrument cluster the combination meter. If the tach/speedo/temp gauge are acting erratic, the combination meter probably requires replacement. The cheapest source for this part will probably be from a local auto recycler.
Tester
Can I just go and have some one run a test with those code checker and will it tell me? Or is this an issue that can not detect? Im trying to find out the cheapest way without having to go to the dealer. My husband is pretty good with vehicles if we know what to fix.?? I dont want to order a part that is not needed, and another and anohter…
Clusters Are Fairly Easy To Remove On Some Makes / Models. I Don’t Know A Nissan Maxima From A Bale Of Hay.
I do know you’ll need a repair / shop manual that has the cluster removal / installation in it.
Also, don’t overlook the possibility that a poor / loose connection(s) is the culprit. I’d wiggle some wires around or plug and unplug some harnesses when I popped that cluster out.
You may not need any parts.
CSA