Am I using the wrong cable?

Hello I have recently installed a cb radio in my Peterbilt 365 I got 2, 4 foot fire sticks the tuneable kind and a uniden pc78ltx radio. I hooked it all up and my swr is basically pegged along with the red antenna light on if I attempt to transmit. I am not using the radio I know I will fry it until I figure out the issue. I attached a picture of the cable that was already in the truck that I connected this connector does not look the same as what I'm used to could this be the problem or do I need to look into grounding my antenna mounts better? The antennas are what look to be factory mirror mounts. Mind you all this is a almost 20 year old truck. Should I get a new coax and just hook it up to one of the antennas and see if that helps?

 

Here's an update I bought a clamp on mirror mount and a new Wilson coax, the radio is now working and the red antenna light is gone. The old studs on the mirrors were badly corroded and the old coax is probably in the same condition. I can now hear people and they can hear me but my swr is still around 2.5 the mirrors are grounded but I'm going to try to add a couple grounds and see if it helps...

 

Thanks for the reply I am using a external swr meter. It's a cheap workman model off Amazon. I setup my cb in my pickup truck when doing hotshot a few years ago with very good results with a cheap uniden radio and fire stick antenna mounted to fender. That's why I went with a nicer uniden and fire stick antenna again for my semi now. I had the mechanic add a ground strap on my down day today I'm going back out for a overnight run tonight at midnight when I park for the day tomorrow around 2pm I will see how the swr is now hopefully it's better. I think that coax cable that was in the truck was very very old. The fittings connected to studs on mirror were so corroded I couldn't even get the to loosen with vice grips. I feel lucky to be driving such a cool old peterbilt heck you could almost call it a classic but stuff like this is kinda the bad side lol. Just glad I get to grab my own gears before manual goes extinct soon..

Will update tomorrow with swr readings maybe some pictures of what I got setup thanks!

 

Am there update I added ground and needed to shorten antenna passed max adjustment on fire stick I read you can remove the adjusting screw completely if you need to shorten more, this worked for me. Not totally happy but have a swe of 1.6 on channel 19 now only thing I can think is to add more grounding throughout the truck at this point....it's a new Wilson cable new antenna and new radio so I'd say that only leaves grounding. I did hear that tilting antenna can sometimes effect swr...this true?