Just adopted a 1 1/2 yr old chiweene and cant housebreak even with crating

Question
My Husband adopted a cute chiweenie for me and I have tried everything to housebreak this dog with no luck. I have tried potty pads, I tried leaving him in a pen outside for up to an hour after he eats and when he should need to go potty, I have tried constant outside trips every hour and I have even tried crating him and bringing him outside every 30 mins to potty after he has eaten. Nothing has worked.  I have him on a regular feeding schedule and I have even tried feeding him a larger breakfast or dinner to see if I can pin point his poo's and pee schedule. Nothing helped.  I am home all day and I have tried keeping him in my sight and right with me in every room I go in and that won't work either he'll just go right in front of me!  I am at my whits end with this dog as I have another dog that is 100% completely housebroken and I have trained many other dogs but I can't seem to train him!  Sometimes when I catch it JUST right he will go outside to potty or poo but it doesn't happen often.  Once when I crated him with his bed in there he poo'd through the bars and then the 2nd time he just covered it up with a blanket I had in there.  Tonight he poo'd in the bedroom close to the doorway and then 4 hrs later he pee'd in his crate on a towel and then tried to cover it up with dry part of the the towel so I wouldn't see it or it wouldn't get on him.  He seems to know he has done something wrong. When I go into a area where he has had an accident he will start looking for a hiding spot right away, like tonight - my husband went towards the bedroom and he took off to hide under the kitchen table, there was no reason for him to go hide other than he saw my husband go towards the bedroom right after he had poo'd.  What do I do with this dog?  Will I EVER be able to house break him?

Answer
Hi Lisa.  This sounds like an incredibly frustrating experience for everyone.  From what you describe, the dog is also very anxious and worried about his elimination routine.  This makes things even worse when the dog feels like he's in trouble for his normal bodily functions.  

Please answer some questions so I can give you more specific advice:
How long has the dog been in your home?
Where was he before you adopted him?
Was he housetrained there?
What brand of food are you feeding him?
Is it kibble or wet food?
Is he neutered?
When he has accidents in the house is it always on a "soft" surface like carpet or towels?
Other than his anxiety about elimination, is he a "worrier" and cautious about new things and people?

Please get back to me with this information and I'll have some specific suggestions for you.