No dash light on 2003 dodge caravan. Have mileage light but no back light to see speedo ect

This could be an issue with the actual speedo cable. When a old/worn cable gets wet it can sometimes slip inside the connection at the speedo or where it connects to the transmission. Does the speedo needle 'wobble' when you travelling at a constant steady speed? This is a sign of a worn cable or the connector it plugs into.
If it is happening when it rains check the cable at the transmission end isn't getting wet from rain getting in somewhere. There is a possibility here that you might need a new speedo cable. There are temporary fixes but it is best to work out if it's something simple like a loose connector.
If you can get access to the connectors at both ends check they aren't loose. Remember this is a 20 year old vehicle, even speedo cables wear out, especially on higher mileage vehicles.

Check the harness plug and wiring going to the cluster first. There shouldnt be a specific fuse for speedo backlighting so i would remove the cluster and check the wiring first. see where it leads, check wiring etc.. Some of these clusters allow you to take the bulbs out and test them individually by twisting them out of the back of the cluster. If they are ALL not lighting i would look more towards, wiring or the cluster itself.. Also, if you have any "check engine" or "service engine soon" lights on the dash take it to advanced auto or autozone and scan the system for codes. they do this for free. Please post codes here if any. If you need further detailed info on any aspect just ask.
Regards,
-Tim

05 Dodge Caravan No Start P0688 bad wire - YouTube

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www.youtube.com/watch?v=yshodC_crqo
Sep 22, 2012 - Uploaded by Brian Mann 2005 dodge caravan crank no start p0688 asd relay circuit ... butdoing the voltage drop on the back of the connector to the ipm to.... ECM PCM STARTER 2003 DODGE GRAND CARAVAN 3.3L V6 WONT START ... 1996, 97, 98 Dodge Caravan Starter install3.8L V6 - Duration: 8:39. by Gary O 4,364 views.

I have 4 dodge caravans. Everyone one of them does this we take it on the freeway get up over 60 mph and it will kick back around. I'm serious it will work fine after. Everyone can do this. I run a small taxi business and we only use dodge caravans.

Try disconnecting the battery for a few minutes alot of times tis can reset it. be sure and disconnect the negative side.

i have the same van (2003), same problems, the deler just replace my PCM cost me $950 van works fine untill now.

there would either be a shorted wire or the computer is malfunctioning. The only way to fix this problem is to have a mechanic put a scanner on your car and test it. AUTOZONE DOES IT FREE other wise it's about $40

it sounds as though your transmission input and output sensors are faulty.they are located on the driver side of transmission.input at front of trans.output at rear of transmission. normally if input sensor is faulty trans will stay in limp mode. if output sensor is faulty speedo will not register. they both resemble temp sensors with elec connectors

First thing I would have checked is the charging system, battery load test, alternator charging, all connections to battery cleaned & checked, as well as any ground straps connected from engine to frame, or firewall.

must be the dash connection in the back, need to demount dash panel, and spray wd40 on the connections.