I take it your companions are still low level? They get sturdier with higher levels. Mine seldom die, even against world bosses and normal difficulty dungeons, but when they do it's usually because they keep standing in red.
You may want to give them heavy armor regardless of their role. I know light armor boosts healing but it does little when they are dead.

Edit: I do use Inner Beast (taunt & +10% damage done to target).

wsmith97ub17_ESO wrote: »

Hi,

Since using them, it seems no matter my situation, the aggro always goes to the companion and they die incredibly fast. I don't run a taunt and neither does my companion. I can have aggro first, then as soon as my healer companion shoots a random beam at the target, they will die soon. Its incredibly annoying and I simply stopped running them at all. I like the idea, but its its just not fun that they die so soon and easily. My companion has blue gear as a reference. I would rather not have to run a taunt, any ideas on why this is or does ZOS think the mechanic ads something to this?

imo as such nothing wrong with the blue companion gear you use
but blue medium or worse blue light armor will give the companion not much armor resistance and therefore vulnerable

Do you use light armor to get the armor passive of more soothing ?

If your companion is a healer, they WILL draw aggro right away. Players learn to target healers first, and ESO monsters are usually scripted to target healers as well. You have to make sure you companion is fully leveled, have APPROPRIATE gear (blues are fine, but you need matching traits too- I mostly use full Quickened, except on tank I'll use Bolstered). But also importantly, you have to make sure you have appropriate skills attached- mainly healing skills. They do very little DPS, so speccing them out as a DPS is usually a good way to have them die quickly. I have Bastian specc'd as a DPS, but I also have him in full blue HEAVY armor with Quickened traits, but I don't use him against difficult enemies either. I have Isobel specc'd full tank, and she rarely dies to World Bosses, however, I still have to offer heals now and then otherwise she will die- but not quickly.

I've found that most people fail with companions because they don't level them, they don't spec them in appropriate gear with useful traits, and they don't slot them with mostly healing/defensive skills. Then wonder why they keep dying. They are not 'player replacements'... they don't have the same capability as another player... so shouldn't be expected to perform like one.

I rarely rarely ever have a companion die, and if they do, it's usually MY fault. The last time I had a companion die was Isobel facing a World Boss and it was because her and I got separated as I was busying interrupting adds from healing the boss and she died during that phase. However, if I can maintain a close distance to her while she's tanking the boss, and offer up heals now and then, she never dies. Understanding what companions can and cannot do and then equipping and playing them accordingly is very important to companion success, or failure. But 9 times out of 10, failure comes down to a player expecting something out of a companion while not putting much understanding into them.

You should hold agro most of the time at least if you use DoT's , found that they rarely draw agro on bosses as they cast much less than me, think agro is recalculated every 7 seconds. An morph of inner fire works as other point out.

wsmith97ub17_ESO wrote: »

The aggro always goes to the companion and they die incredibly fast.

There are 2 parts to your problem, companions getting agro (inevitable), AND companions dying fast (user error). Some great tips here, but I think the most obvious tip was overlooked - direct your melee companions to fight where you want to bunch up enemies.

A well designed companion will help you with crowd control by gathering up mobs and bringing them where you choose.

Here is a max-level Ember DPS build that has great survivability, good enough self-healing, and is designed to gather tonnes of agro and thrive in the middle of a dog-pile.